Making beautiful music: The state of the art in mobile technology and how we can make the most of it in libraries

Mobile technology is in a great state of flux and competition and the bar keeps getting set higher. What models of service are leading the pack? Should libraries be providing mobile devices or rather, should libraries be providing content for any kind of device and leave the choice of device to our patrons? This session will explore the most recent trends so that attendees can get a sense of the marketplace and what might work best in their own context. Many libraries are experimenting with handheld readers such as Kindle, Nook and iPads, and at the same time testing out various platforms to deliver e-content (such as Overdrive and 3-M Cloud Library)

Brownian motion of solitons in a Bose-Einstein Condensate

For the first time, we observed and controlled the Brownian motion of solitons. We launched solitonic excitations in highly elongated $^{87}\rm{Rb}$ BECs and showed that a dilute background of impurity atoms in a different internal state dramatically affects the soliton. With no impurities and in one-dimension (1-D), these solitons would have an infinite lifetime, a consequence of integrability. In our experiment, the added impurities scatter off the much larger soliton, contributing to its Brownian motion and decreasing its lifetime. We describe the soliton's diffusive behavior using a quasi-1-D scattering theory of impurity atoms interacting with a soliton, giving diffusion coefficients consistent with experiment.Comment: 4 figure

Sport supplement use predicts doping likelihood via sport supplement beliefs

Introduction The gateway hypothesis posits that athletes are at risk of progressing to doping if sport supplements are already used for performance enhancement. Recent research has indicated that athletes with stronger beliefs in the effectiveness of sport supplements in improving performance are more likely to use sport supplements (1). Hypothetically, therefore, if athletes’ beliefs about sports supplements influence supplement use, and if supplement use predicts doping (i.e. the gateway hypothesis), it is reasonable to suggest a relationship between beliefs about supplements and doping likelihood. However, this relationship remains untested. This study aimed to test the mediating role of sport supplement beliefs on the relationship between sport supplement use and doping likelihood. Method Four hundred and eighty one competitive athletes (mean + SD: age = 19.6 ± 2.2 yrs, hour per week training = 6.3 ± 4.5, years competing = 5.9 ± 4.6) were recruited from sports clubs and asked to complete measures of sport supplement use, sport supplement beliefs and doping likelihood. Results Sport supplement use was associated with sport supplement beliefs (r = 0.46, p <0.01) and doping likelihood (r = 0.14, p < 0.01), and sport supplement beliefs were correlated with doping likelihood (r = 0.22, p <0.01). Mediation analysis indicated that sport supplement beliefs significantly mediated the relationship between sport supplement use and doping likelihood (β = 0.20, 95% CI = 0.10 to 0.30), whereas sport supplement use was not directly related to doping likelihood (β = 0.04, 95% CI = -0.05 to 0.15). Conclusion The results of this study indicate sport supplement use predicts doping likelihood via sport supplement beliefs. These findings provide novel evidence to suggest that athletes using sport supplements are more likely to dope due to their belief in the effectiveness of these substances and could help further explain why athletes using sport supplements are more likely to progress to doping (i.e. gateway hypothesis)

Sport supplement use predicts doping attitudes and likelihood via sport supplement beliefs

The aim of this study was to examine: 1) whether sport supplement use is related to doping and 2) whether sport supplement beliefs mediated this relationship. In Study 1, athletes (N = 598), completed measures of sport supplement use, sport supplement beliefs, and doping attitudes. In Study 2, athletes (N = 475) completed measures of sport supplement use, sport supplement beliefs, and doping likelihood. In both studies, sport supplement use predicted doping outcomes indirectly via sport supplement beliefs. Our findings provide novel evidence to suggest that sport supplement users, who strongly believe that sport supplements are effective, are more likely to dope. For anti-doping organisations wishing to prevent doping, targeting an athlete’s beliefs about sport supplements may improve the effectiveness of anti-doping prevention programmes

The development of a menthol solution for use during sport and exercise

Menthol mouth-swilling has been shown to improve performance across differing exercise modalities, yet no work has been conducted to ascertain the preferred concentration of menthol within a swill. Colour has also been shown to influence psychophysiological outcomes, and may influence the efficacy of ergogenic aids. We conducted two experiments: one to ascertain preferred menthol concentration (0.005–0.105% menthol), the second to assess colour preference (Light Blue,Dark Blue, Light Green, Dark Green, Red). Participants rated swills for Smell, Taste, Freshness, Mouth Feel and Irritation (plus Appearance in the second trial) via 15 cm Visual Analogue Scales (VAS), having swilled and expectorated 25 mL of fluid. Both trials employed a crossover design, with tasting order assigned by Latin squares. Differences were assessed for statistical significance (p < 0.05) using one-way repeated measures ANOVAs. Standardised mean differences �90% confidence intervals were calculated to assess the magnitude of any observed differences. No significant differences were found between concentrations for total VAS score, but higher concentrations demonstrated a greater number of small effects. Similarly, no significant differences between colours were found. Small effects were found when Light Green was compared to Dark Green and Red. Effects were trivial when Light Green was compared to Light Blue (0.05 � 0.20) and Dark Blue (0.19 � 0.32). We recommend athletes employ a Light Green or Light Blue 0.1% menthol mouth-swill

Measurement-induced dynamics and stabilization of spinor-condensate domain walls

Weakly measuring many-body systems and allowing for feedback in real-time can simultaneously create and measure new phenomena in strongly correlated quantum systems. We study the dynamics of a continuously measured two-component Bose-Einstein condensate (BEC) potentially containing a domain wall, and focus on the trade-off between usable information obtained from measurement and quantum backaction. Each weakly measured system yields a measurement record from which we extract real-time dynamics of the domain wall. We show that quantum backaction due to measurement causes two primary effects: domain wall diffusion and overall heating. The system dynamics and signal-to-noise ratio depend on the choice of measurement observable. We describe a feedback protocol to create and stabilize a domain wall in the regime where domain walls are unstable, giving a prototype example of Hamiltonian engineering using measurement and feedback

Feedback induced magnetic phases in binary Bose-Einstein condensates

Weak measurement in tandem with real-time feedback control is a new route toward engineering novel non-equilibrium quantum matter. Here we develop a theoretical toolbox for quantum feedback control of multicomponent Bose-Einstein condensates (BECs) using backaction-limited weak measurements in conjunction with spatially resolved feedback. Feedback in the form of a single-particle potential can introduce effective interactions that enter into the stochastic equation governing system dynamics. The effective interactions are tunable and can be made analogous to Feshbach resonances -- spin-independent and spin-dependent -- but without changing atomic scattering parameters. Feedback cooling prevents runaway heating due to measurement backaction and we present an analytical model to explain its effectiveness. We showcase our toolbox by studying a two-component BEC using a stochastic mean-field theory, where feedback induces a phase transition between easy-axis ferromagnet and spin-disordered paramagnet phases. We present the steady-state phase diagram as a function of intrinsic and effective spin-dependent interaction strengths. Our result demonstrates that closed-loop quantum control of Bose-Einstein condensates is a powerful new tool for quantum engineering in cold-atom systems

Metabolic trade-offs and the maintenance of the fittest and the flattest.

This is the post print version of the article, deposited in accordance with SHERPA RoMEO guidelines. The final definitive version is available from: http://www.nature.com/nature/journal/v472/n7343/full/nature09905.htmlHow is diversity maintained? Environmental heterogeneity is considered to be important, yet diversity in seemingly homogeneous environments is nonetheless observed. This, it is assumed, must either be owing to weak selection, mutational input or a fitness advantage to genotypes when rare. Here we demonstrate the possibility of a new general mechanism of stable diversity maintenance, one that stems from metabolic and physiological trade-offs. The model requires that such trade-offs translate into a fitness landscape in which the most fit has unfit near-mutational neighbours, and a lower fitness peak also exists that is more mutationally robust. The 'survival of the fittest' applies at low mutation rates, giving way to 'survival of the flattest' at high mutation rates. However, as a consequence of quasispecies-level negative frequency-dependent selection and differences in mutational robustness we observe a transition zone in which both fittest and flattest coexist. Although diversity maintenance is possible for simple organisms in simple environments, the more trade-offs there are, the wider the maintenance zone becomes. The principle may be applied to lineages within a species or species within a community, potentially explaining why competitive exclusion need not be observed in homogeneous environments. This principle predicts the enigmatic richness of metabolic strategies in clonal bacteria and questions the safety of lethal mutagenesis as an antimicrobial treatment

Feedback cooled Bose-Einstein condensation: near and far from equilibrium

Continuously measured interacting quantum systems almost invariably heat, causing loss of quantum coherence. Here, we study Bose-Einstein condensates (BECs) subject to repeated weak measurement of the atomic density and describe several protocols for generating a feedback signal designed to remove excitations created by measurement backaction. We use a stochastic Gross-Pitaevskii equation to model the system dynamics and find that a feedback protocol utilizing momentum dependant gain and filtering can effectively cool both 1D and 2D systems. The performance of these protocols is quantified in terms of the steady state energy, entropy, and condensed fraction. These are the first feedback cooling protocols demonstrated in 2D, and in 1D our optimal protocol reduces the equilibrium energy by more than a factor of 100 as compared with a previous cooling protocol developed using the same methodology. We also use this protocol to quench-cool 1D BECs from non-condensed highly excited states and find that they rapidly condense into a far from equilibrium state with energy orders of magnitude higher than the equilibrium ground state energy for that condensate fraction. We explain this in terms of the near-integrability of our 1D system, whereby efficiently cooled low momentum modes are effectively decoupled from the energetic `reservoir' of the higher momentum modes. We observe that the quench-cooled condensed states can have non-zero integer winding numbers described by quantized supercurrents.Comment: 14 pages, 7 figure

Entropy of the Nordic electricity market: anomalous scaling, spikes, and mean-reversion

The electricity market is a very peculiar market due to the large variety of phenomena that can affect the spot price. However, this market still shows many typical features of other speculative (commodity) markets like, for instance, data clustering and mean reversion. We apply the diffusion entropy analysis (DEA) to the Nordic spot electricity market (Nord Pool). We study the waiting time statistics between consecutive spot price spikes and find it to show anomalous scaling characterized by a decaying power-law. The exponent observed in data follows a quite robust relationship with the one implied by the DEA analysis. We also in terms of the DEA revisit topics like clustering, mean-reversion and periodicities. We finally propose a GARCH inspired model but for the price itself. Models in the context of stochastic volatility processes appear under this scope to have a feasible description.Comment: 16 pages, 7 figure