Interface-mediated interactions: Entropic forces of curved membranes

Particles embedded in a fluctuating interface experience forces and torques mediated by the deformations and by the thermal fluctuations of the medium. Considering a system of two cylinders bound to a fluid membrane we show that the entropic contribution enhances the curvature-mediated repulsion between the two cylinders. This is contrary to the usual attractive Casimir force in the absence of curvature-mediated interactions. For a large distance between the cylinders, we retrieve the renormalization of the surface tension of a flat membrane due to thermal fluctuations.Comment: 11 pages, 5 figures; final version, as appeared in Phys. Rev.

Are multimedia identification tools biodiversity-friendly?

This paper discusses the results of the LifeCLEF 2014 multimedia identification challenges with regards to the requirements of real-world ecological surveillance systems. In particular, we study the identification performances of the evaluated systems as a function of the ordinariness or rarity of the species in the dataset. This allows us to assess the ability of the underlying methods to be robust to heavily tailed distributions such as the ones encountered in real-world collections of life observations. Results show that all methods are more or less affected by the long-tail curse but that the best methods making use of classifiers with good discrimi- nation capacities do resist the phenomenon pretty well

Universal Heat Conduction in YBa_2Cu_3O_6.9

The thermal conductivity of YBa_2Cu_3O_6.9 was measured at low temperatures in untwinned single crystals with concentrations of Zn impurities from 0 to 3% of Cu. A linear term kappa_0/T = 0.19 mW/K^2.cm is clearly resolved as T -> 0, and found to be virtually independent of Zn concentration. The existence of this residual normal fluid strongly validates the basic theory of transport in unconventional superconductors. Moreover, the observed universal behavior is in quantitative agreement with calculations for a gap function of d-wave symmetry.Comment: Latex file, 4 pages, 3 EPS figures, to appear in Physical Review Letter

LifeCLEF: Multimedia Life Species Identification

EMR co-located with ACM International Conference on Multimedia Retrieval (ICMR)International audienceBuilding accurate knowledge of the identity, the geographicdistribution and the evolution of living species is essentialfor a sustainable development of humanity as well as forbiodiversity conservation. In this context, using multimediaidentication tools is considered as one of the most promisingsolution to help bridging the taxonomic gap. With therecent advances in digital devices/equipment, network bandwidthand information storage capacities, the production ofmultimedia big data has indeed become an easy task. In parallel,the emergence of citizen sciences and social networkingtools has fostered the creation of large and structured communitiesof nature observers (e.g. eBird, Xeno-canto, TelaBotanica, etc.) that have started to produce outstandingcollections of multimedia records. Unfortunately, the performanceof the state-of-the-art multimedia analysis techniqueson such data is still not well understood and is far fromreaching the real world's requirements in terms of identi-cation tools. The LifeCLEF lab proposes to evaluate thesechallenges around 3 tasks related to multimedia informationretrieval and ne-grained classication problems in 3 livingworlds. Each task is based on large and real-world data andthe measured challenges are dened in collaboration withbiologists and environmental stakeholders in order to reflect realistic usage scenarios

Investigating gender differences in the factor structure of the Gudjonsson Compliance Scale

Purpose: The Gudjonsson Compliance Scale (GCS) remains, in terms of its psychometrics, an under-researched instrument, in which gender differences in particular have been insufficiently examined. The aim of this research was to therefore investigate the effect of gender on the factor structure of the GCS. Method: The GCS was administered to 441 females and 250 males. The data were factor-analysed, with 1-, 2-, 3-, and 4-factor solutions tested and compared. Procrustean rotation was applied to the male factor loading matrix to investigate structural equivalence across gender. Results: Although a 3-factor solution was the best fit to the male GCS data, a 4-factor solution was the most acceptable fit to the female data. Whilst each of the factors had a high degree of determinacy, the identity coefficients indicated that these factors differ non-trivially across gender. Conclusion: The GCS may measure different aspects of compliance across males and females, which may explain the gender differences in compliance found within the literature to date. The work also allows insight into why males and females may end up complying with police requests, which might ultimately help to inform strategies, implemented by police, to manage vulnerable general population suspects and witnesses. There is a need now to further investigate the structure of compliance across ethnic groups and/or countries where the GCS is administered

Measurement of W Polarisation at LEP

The three different helicity states of W bosons produced in the reaction e+ e- -> W+ W- -> l nu q q~ at LEP are studied using leptonic and hadronic W decays. Data at centre-of-mass energies \sqrt s = 183-209 GeV are used to measure the polarisation of W bosons, and its dependence on the W boson production angle. The fraction of longitudinally polarised W bosons is measured to be 0.218 \pm 0.027 \pm 0.016 where the first uncertainty is statistical and the second systematic, in agreement with the Standard Model expectation

Search for Anomalous Couplings in the Higgs Sector at LEP

Anomalous couplings of the Higgs boson are searched for through the processes e^+ e^- -> H gamma, e^+ e^- -> e^+ e^- H and e^+ e^- -> HZ. The mass range 70 GeV < m_H < 190 GeV is explored using 602 pb^-1 of integrated luminosity collected with the L3 detector at LEP at centre-of-mass energies sqrt(s)=189-209 GeV. The Higgs decay channels H -> ffbar, H -> gamma gamma, H -> Z\gamma and H -> WW^(*) are considered and no evidence is found for anomalous Higgs production or decay. Limits on the anomalous couplings d, db, Delta(g1z), Delta(kappa_gamma) and xi^2 are derived as well as limits on the H -> gamma gamma and H -> Z gamma decay rates

Measurement of W Polarisation at LEP

The three different helicity states of W bosons produced in the reaction e+ e- -> W+ W- -> l nu q q~ at LEP are studied using leptonic and hadronic W decays. Data at centre-of-mass energies \sqrt s = 183-209 GeV are used to measure the polarisation of W bosons, and its dependence on the W boson production angle. The fraction of longitudinally polarised W bosons is measured to be 0.218 \pm 0.027 \pm 0.016 where the first uncertainty is statistical and the second systematic, in agreement with the Standard Model expectation

Neutral-Current Four-Fermion Production in e+e- Interactions at LEP

Neutral-current four-fermion production, e+e- -> ffff is studied in 0.7/fb of data collected with the L3 detector at LEP at centre-of-mass energies root(s)=183-209GeV. Four final states are considered: qqvv, qqll, llll and llvv, where l denotes either an electron or a muon. Their cross sections are measured and found to agree with the Standard Model predictions. In addition, the e+e- -> Zgamma* -> ffff process is studied and its total cross section at the average centre-of-mass energy 196.6GeV is found to be 0.29 +/- 0.05 +/- 0.03 pb, where the first uncertainty is statistical and the second systematic, in agreement with the Standard Model prediction of 0.22 pb. Finally, the mass spectra of the qqll final states are analysed to search for the possible production of a new neutral heavy particle, for which no evidence is found