70 research outputs found

    The 72-Hour WEBT Microvariability Observation of Blazar S5 0716+714 in 2009

    Full text link
    Context. The international whole earth blazar telescope (WEBT) consortium planned and carried out three days of intensive micro-variability observations of S5 0716+714 from February 22, 2009 to February 25, 2009. This object was chosen due to its bright apparent magnitude range, its high declination, and its very large duty cycle for micro-variations. Aims. We report here on the long continuous optical micro-variability light curve of 0716+714 obtained during the multi-site observing campaign during which the Blazar showed almost constant variability over a 0.5 magnitude range. The resulting light curve is presented here for the first time. Observations from participating observatories were corrected for instrumental differences and combined to construct the overall smoothed light curve. Methods. Thirty-six observatories in sixteen countries participated in this continuous monitoring program and twenty of them submitted data for compilation into a continuous light curve. The light curve was analyzed using several techniques including Fourier transform, Wavelet and noise analysis techniques. Those results led us to model the light curve by attributing the variations to a series of synchrotron pulses. Results. We have interpreted the observed microvariations in this extended light curve in terms of a new model consisting of individual stochastic pulses due to cells in a turbulent jet which are energized by a passing shock and cool by means of synchrotron emission. We obtained an excellent fit to the 72-hour light curve with the synchrotron pulse model

    Planet Hunters. VIII. Characterization of 41 Long-Period Exoplanet Candidates from Kepler Archival Data

    Get PDF
    The census of exoplanets is incomplete for orbital distances larger than 1 AU. Here, we present 41 long-period planet candidates in 38 systems identified by Planet Hunters based on Kepler archival data (Q0-Q17). Among them, 17 exhibit only one transit, 14 have two visible transits and 10 have more than three visible transits. For planet candidates with only one visible transit, we estimate their orbital periods based on transit duration and host star properties. The majority of the planet candidates in this work (75%) have orbital periods that correspond to distances of 1-3 AU from their host stars. We conduct follow-up imaging and spectroscopic observations to validate and characterize planet host stars. In total, we obtain adaptive optics images for 33 stars to search for possible blending sources. Six stars have stellar companions within 4". We obtain high-resolution spectra for 6 stars to determine their physical properties. Stellar properties for other stars are obtained from the NASA Exoplanet Archive and the Kepler Stellar Catalog by Huber et al. (2014). We validate 7 planet candidates that have planet confidence over 0.997 (3-{\sigma} level). These validated planets include 3 single-transit planets (KIC-3558849b, KIC-5951458b, and KIC-8540376c), 3 planets with double transits (KIC-8540376b, KIC-9663113b, and KIC-10525077b), and 1 planet with 4 transits (KIC-5437945b). This work provides assessment regarding the existence of planets at wide separations and the associated false positive rate for transiting observation (17%-33%). More than half of the long-period planets with at least three transits in this paper exhibit transit timing variations up to 41 hours, which suggest additional components that dynamically interact with the transiting planet candidates. The nature of these components can be determined by follow-up radial velocity and transit observations.Comment: Published on ApJ, 815, 127 Notations of validated planets are changed in accordance with naming convention of NASA Exoplanet Archiv

    Proteins on the catwalk: modelling the structural domains of the CCN family of proteins

    Get PDF
    The CCN family of proteins (CCN1, CCN2, CCN3, CCN4, CCN5 and CCN6) are multifunctional mosaic proteins that play keys roles in crucial areas of physiology such as angiogenesis, skeletal development tumourigenesis, cell proliferation, adhesion and survival. This expansive repertoire of functions comes through a modular structure of 4 discrete domains that act both independently and in concert. How these interactions with ligands and with neighbouring domains lead to the biological effects is still to be explored but the molecular structure of the domains is likely to play an important role in this. In this review we have highlighted some of the key features of the individual domains of CCN family of proteins based on their biological effects using a homology modelling approach

    Mental Symptoms and the Use of New Technical Equipment

    No full text
    The aim of this paper was to present how mental symptoms are connected to the use of desktop, portable or minicomputers (communicators and hand-held computers), mobile phones, and background information such as age and gender in the Finnish working-age population. The study was carried out as a cross-sectional study by posting a questionnaire to 15 000 working-age (18–65) Finns. The mental symptoms of 6 121 respondents were analysed using the model factors age, gender, the use of computers and the use of mobile phones. In all data, the use of desktop computers was related to mental symptoms. However, the results of our data are not highly reliable, because the nonresponse rate was over 50%. Nevertheless, it may be essential to take into account in the future that working with computers can increase workers’ mental symptoms, and it is important to observe their mental health

    Evaluation of the Increased Accident Risk From Workplace Noise

    No full text
    Directive 2003/10/EC sets the requirement for evaluating the effect of noise on accident risk. Accident risk is elevated for workers with a hearing handicap because of their reduced speech intelligibility and reduced capability to perceive the direction of incoming sound. An audiogram is not a good method for the evaluation of these functions. To reduce accident risk, organisational and personal solutions are needed. For both methods, efficiency must be evaluated through proper risk assessment. Because practical guidelines are not available, this paper presents principles for accident risk evaluation techniques
    • …
    corecore