952 research outputs found

    The Effects of Coworker Relationships, Involvement, and Supportiveness on Job Satisfaction and Performance

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    Past research has indicated that relationships, involvement, and supportiveness have an effect on job satisfaction and performance. A study was done on Gettysburg College students who have had experience with group work. Sixty-four (29 males, 35 females) Gettysburg College students were used as participants in the study. The study was split fairly evenly between sophomores, juniors, and seniors. To start, the survey included two demographic questions: gender and class year. Participants completed an online survey about the relationships among group mates, group involvement, and group support experience. Questions about the overall satisfaction and performance were also included. A correlational design was used to analyze the data. The results of this study concluded that there was significant association between positive relationships and involvement and job satisfaction and group performance in a group scenario. There was a significant association between group support and job satisfaction, but not performance

    Optical phase coherent timing of the Crab nebula pulsar with Iqueye at the ESO New Technology Telescope

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    The Crab nebula pulsar was observed in 2009 January and December with a novel very fast optical photon counter, Iqueye, mounted at the ESO 3.5 m New Technology Telescope. Thanks to the exquisite quality of the Iqueye data, we computed accurate phase coherent timing solutions for the two observing runs and over the entire year 2009. Our statistical uncertainty on the determination of the phase of the main pulse and the rotational period of the pulsar for short (a few days) time intervals are ≈1 μ\approx 1 \, \mus and ~0.5 ps, respectively. Comparison with the Jodrell Bank radio ephemerides shows that the optical pulse leads the radio one by ~240 μ\mus in January and ~160 μ\mus in December, in agreement with a number of other measurements performed after 1996. A third-order polynomial fit adequately describes the spin-down for the 2009 January plus December optical observations. The phase noise is consistent with being Gaussian distributed with a dispersion σ\sigma of ≈15 μ\approx 15 \, \mus in most observations, in agreement with theoretical expectations for photon noise-induced phase variability.Comment: 10 pages, 5 figures. Accepted for publication in Monthly Notices of the Royal Astronomical Societ

    Aqueye optical observations of the Crab Nebula pulsar

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    We observed the Crab pulsar in October 2008 at the Copernico Telescope in Asiago - Cima Ekar with the optical photon counter Aqueye (the Asiago Quantum Eye) which has the best temporal resolution and accuracy ever achieved in the optical domain (hundreds of picoseconds). Our goal was to perform a detailed analysis of the optical period and phase drift of the main peak of the Crab pulsar and compare it with the Jodrell Bank ephemerides. We determined the position of the main peak using the steepest zero of the cross-correlation function between the pulsar signal and an accurate optical template. The pulsar rotational period and period derivative have been measured with great accuracy using observations covering only a 2 day time interval. The error on the period is 1.7 ps, limited only by the statistical uncertainty. Both the rotational frequency and its first derivative are in agreement with those from the Jodrell Bank radio ephemerides archive. We also found evidence of the optical peak leading the radio one by ~230 microseconds. The distribution of phase-residuals of the whole dataset is slightly wider than that of a synthetic signal generated as a sequence of pulses distributed in time with the probability proportional to the pulse shape, such as the average count rate and background level are those of the Crab pulsar observed with Aqueye. The counting statistics and quality of the data allowed us to determine the pulsar period and period derivative with great accuracy in 2 days only. The time of arrival of the optical peak of the Crab pulsar leads the radio one in agreement with what recently reported in the literature. The distribution of the phase residuals can be approximated with a Gaussian and is consistent with being completely caused by photon noise (for the best data sets).Comment: 7 pages, 7 figures. Accepted for publication in Astronomy and Astrophysic

    Neoproterozoic reworking of the Palaeoproterozoic Capricorn Orogen of Western Australia and implications for the amalgamation of Rodinia

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    Argon isotopic data from mica from the southern Capricorn region of Western Australia record complex intra- and inter-grain systematics that reflect modification due to a range of processes. However, 40Ar/39Ar age distributions, though complex, generally show early Neoproterozoic ages in the west, increasing to Mesoproterozoic ages in the east. Palaeoproterozoic ages associated with cooling after the c.1.8 Ga Capricorn Orogen or c.1.6 Ga Mangaroon Orogen are not preserved. These data reflect cooling from a ~300C thermal overprint that took place prior to 960 Ma that is related to the enigmatic Edmunian Orogeny. These data, combined with sediment provenance data from the Early Neoproterozoic Officer Basin and U-Pb age data from the nearby Pinjarra Orogen, indicate that the late Mesoproterozoic - Neoproterozoic Pinjarra and Edmundian events are dynamically linked and reflect tectonic activity on the western margin of the amalgamated West Australian Craton. The temporal framework for this event suggest a link to the evolving Rodinian supercontinent and reflect the oblique collision of either Greater India or Kalahari cratons with the West Australian Craton. These results illustrate that the temporal evolution of poorly preserved orogens can be constrained by low-temperature thermochronology in the adjacent cratons

    Finite element analysis of ground deformation due to dike intrusion with applications to Mt. Etna volcano

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    A 2D finite elements study was carried out to analyse the effects caused by dike intrusion inside a heterogeneous medium and with a realistic topography of Mt. Etna volcano. Firstly, the method (dimension domain, elements type) was calibrated using plane strain models in elastic half-spaces; the results were compared with those obtained from analytical dislocation models. Then the effects caused both by the topographic variations and the presence of multi-layered medium on the surface, were studied. In particular, an application was then considered to Mt. Etna by taking into account the real topography and the stratification deduced from seismic tomography. In these conditions, the effects expected by the dike, employed to model the 2001 eruption under simple elastic half-space medium conditions, were computed, showing that topography is extremely important, at least in the near field
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