384 research outputs found

    Pinning an Ion with an Intracavity Optical Lattice

    Full text link
    We report one-dimensional pinning of a single ion by an optical lattice. The lattice potential is produced by a standing-wave cavity along the rf-field-free axis of a linear Paul trap. The ion's localization is detected by measuring its fluorescence when excited by standing-wave fields with the same period, but different spatial phases. The experiments agree with an analytical model of the localization process, which we test against numerical simulations. For the best localization achieved, the ion's average coupling to the cavity field is enhanced from 50% to 81(3)% of its maximum possible value, and we infer that the ion is bound in a lattice well with over 97% probability.Comment: 5 pages, 4 figures; Text edited for clarity, results unchange

    Phase I, randomized, observer-blind, placebo-controlled studies to evaluate the safety, reactogenicity and immunogenicity of an investigational non-typeable Haemophilus influenzae (NTHi) protein vaccine in adults

    Get PDF
    Background: Non-typeable Haemophilus influenzae (NTHi) is a major cause of various respiratory diseases. The development of an effective vaccine against NTHi mandates new approaches beyond conjugated vaccines as this opportunistic bacterium is non-encapsulated. Here we report on the safety, reactogenicity and immunogenicity of a multi-component investigational vaccine based on three conserved surface proteins from NTHi (proteins D [PD],E [PE] and Pilin A [PilA]) in two observer-blind phase I studies. Methods: In the first study (NCT01657526), 48 healthy 18-40 year-olds received two vaccine formulations (10 or 30 mu g of each antigen [PD and a fusion protein PE-PilA]) or saline placebo at months 0 and 2. In the second study (NCT01678677), 270 50-70 year-olds, current or former smokers, received eight vaccine formulations (10 or 30 mu g antigen/dose non-adjuvanted or adjuvanted with alum, AS01(E) or ASO4(c)) or saline placebo at months 0,2 and 6 (plain and alum-adjuvanted groups) and at months 0 and 2 (AS-adjuvanted groups). Solicited and unsolicited adverse events (AEs) were recorded for 7 and 30 days post-vaccination, respectively; potential immune-mediated diseases (pIMDs) and serious AEs (SAEs) throughout the studies. Humoral and antigen-specific T-cell immunity (in study 2 only) responses were assessed up to 12 months post-vaccination. Results: Observed reactogenicity was highest in the AS-adjuvanted groups but no safety concerns were identified with any of the NTHi vaccine formulations. One fatal SAE (cardiac arrest) not considered related to vaccination, and one pIMD (non-serious psoriasis) in the Placebo group, were reported post-dose 3 in Study 2. All formulations generated a robust antibody response while the AS01-adjuvanted formulations produced the highest humoral and cellular immune responses. Conclusion: This study confirms that the NTHi vaccine formulations had an acceptable reactogenicity and safety profile and were immunogenic in adults. These results justify further clinical development of this NTHi vaccine candidate

    Reservoir computing with the frequency, phase and amplitude of spin-torque nano-oscillators

    Full text link
    Spin-torque nano-oscillators can emulate neurons at the nanoscale. Recent works show that the non-linearity of their oscillation amplitude can be leveraged to achieve waveform classification for an input signal encoded in the amplitude of the input voltage. Here we show that the frequency and the phase of the oscillator can also be used to recognize waveforms. For this purpose, we phase-lock the oscillator to the input waveform, which carries information in its modulated frequency. In this way we considerably decrease amplitude, phase and frequency noise. We show that this method allows classifying sine and square waveforms with an accuracy above 99% when decoding the output from the oscillator amplitude, phase or frequency. We find that recognition rates are directly related to the noise and non-linearity of each variable. These results prove that spin-torque nano-oscillators offer an interesting platform to implement different computing schemes leveraging their rich dynamical features

    High quality factor nitride-based optical cavities: microdisks with embedded GaN/Al(Ga)N quantum dots

    Get PDF
    We compare the quality factor values of the whispery gallery modes of microdisks incorporating GaN quantum dots (QDs) grown on AlN and AlGaN barriers by performing room temperature photoluminescence (PL) spectroscopy. The PL measurements show a large number of high Q factor (Q) resonant modes on the whole spectrum which allows us to identify the different radial mode families and to compare them with simulations. We report a considerable improvement of the Q factor which reflect the etching quality and the relatively low cavity loss by inserting QDs into the cavity. GaN/AlN QDs based microdisks show very high Q values (Q > 7000) whereas the Q factor is only up to 2000 in microdisks embedding QDs grown on AlGaN barrier layer. We attribute this difference to the lower absorption below bandgap for AlN barrier layers at the energies of our experimental investigation

    Anharmonic suppression of Charge density wave in 2H-NbS2_2

    Get PDF
    The temperature dependence of the phonon spectrum in the superconducting transition metal dichalcogenide 2H-NbS2_2 is measured by diffuse and inelastic x-ray scattering. A deep, wide and strongly temperature dependent softening, of the two lowest energy longitudinal phonons bands, appears along the ΓM\mathrm{\Gamma M} symmetry line in reciprocal space. In sharp contrast to the iso-electronic compounds 2H-NbSe2_2, the soft phonons energies are finite, even at very low temperature, and no charge density wave instability occurs, in disagreement with harmonic ab-initio calculations. We show that 2H-NbS2_2 is at the verge of the charge density wave transition and its occurrence is only suppressed by the large anharmonic effects. Moreover, the anharmonicity and the electron phonon coupling both show a strong in-plane anisotropy.Comment: 6 pages, 5 figures, accepted for publication in Physical Review

    How interdisciplinary teamwork contributes to psychosocial cancer support

    Get PDF
    Background: The organization of psychosocial care is rather complex, and its provision diverse. Access is affected by the acceptance and attitude of patients and professional caregivers toward psychosocial care. Objectives: The aims of this study were to examine when patients with cancer experience quality psychosocial care and to identify circumstances in collaboration that contribute to patient-perceived positive psychosocial care. Methods: This study used a qualitative design in which semistructured interviews were conducted with patients, hospital workers, and primary health professionals. Results: Psychosocial care is often requested but also refused by patients with cancer. Based on this discrepancy, a distinction is made between psychosocial support and psychosocial interventions. Psychosocial support aims to reduce the chaos in patients" lives caused by cancer and is not shunned by patients. Psychosocial interventions comprise the formal care offered in response to psychosocial problems. Numerous patients are reluctant to use psychosocial interventions, which are often provided by psychologists. Conclusion: Psychosocial care aims to assist patients in bearing the difficulties of cancer and its treatment. Patients prefer informal support, given often in conjunction with physical care. Implications for Practice: This study confirms the important role of nurses in promoting psychosocial care. Patients perceive much support from nurses, although nurses are not considered to be professional psychosocial caregivers. Being perceived as approachable and trustworthy offers nurses a significant opportunity to bring more intense psychosocial interventions within reach of cancer patients

    Disentangling factors of landscape changes in Burkina Faso, the nexus between spatial modeling and remote sensing

    Full text link
    Rural areas of West Burkina Faso have seen notable transformations these last two decades due to high population growth and farming systems evolution. Satellite images acquired frequently and covering large areas are essential for detecting such landscape changes and long term trends. However, these images generally have coarse spatial resolutions and can only provide information about changes in the main vegetation patterns. The factors causing these changes are more difficult to determine, although there are essential for monitoring landscape evolution. We hereby present a method based on multi-scalar modelling of past landscape dynamics crossed with changes in vegetation trends identified from coarse resolution satellite images. The aim of our presentation is to use the model to simulate and illustrate how land cover and land use changes may impact vegetation response by improving the qualification and understanding of the observed trends. The cropping systems dynamics of the study area, the Tuy province of West Burkina Faso, were modelled with the Ocelet Modelling Platform over the last fifteen years through a multi-scalar model. The model was validated at local scale with information derived from high resolution images. At the same time, vegetation trends were analysed using Ordinary Least Square regressions based on MODIS NDVI time series. Simulated cropland change maps were then used to decompose the remote sensing-based trends. This allowed the spatial identification of factors responsible for the vegetation changes. The original approach we proposed here opens new opportunities for the understanding and monitoring of landscape changes using time series of coarse resolution satellite images
    corecore