4,374 research outputs found

    Biodiversity and Ecosystem Health of the Aldabra Group, Southern Seychelles: Scientific Report to the Government of Seychelles.

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    National Geographic's Pristine Seas project, in collaboration with the government of the Seychelles, the Island Conservation Society (ICS), the Seychelles Islands Foundation (SIF), and the Waitt Foundation, conducted an expedition to explore the poorly known marine environment around these islands. The goals were to assess the biodiversity of the nearshore marine environment and to survey the largely unknown deep sea realm. The data collected contribute to the marine spatial planning of the Seychelles, in particular the creation of large marine reserves

    Generational differences and Fly-In-Fly-Out (FIFO) employee turnover

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    Fly-in, fly-out (FIFO) mining has experienced significant growth in the past decade and is now a typical form of employment in the sector in Australia. Evidence suggests that there are relatively high turnover levels amongst these employees. Whilst there are many contributing causes to this, there may be variances between different generational cohorts at work as arguably their workplace expectation differs. This paper investigates whether turnover intentions vary between different generations of employees. Using a questionnaire, employees were asked about their turnover intentions and this was compared against the groups of Baby Boomers, Generation X and Generation Y. Findings show that Generation Y employees had a higher intention to quit than the Baby Boomers but were no different to Generation X employees

    Could on-the-job embeddedness help bind FIFO workers to their jobs?

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    Fly-In Fly-Out (FIFO) employees in the mining industry in Western Australia have had high levels of turnover, resulting in high costs in recruitment, training and lost production. This research is seeking to understand the reasons for high turnover in this somewhat unusual group of employees. Whilst the research has utilised the more traditional approach to understanding labour turnover, that is that dissatisfaction with job or company and the availability of viable alternatives lead to intention to quit, preliminary results indicate that job embeddedness theory, may provide a better understanding of why FIFO workers choose to stay in their jobs. This outcome raises questions about embeddedness theory itself, namely whether on-the-job embeddedness is a stronger predictor of staying than is off-the-job embeddedness

    Robust array configuration for a microwave interferometric radiometer: application to the geoSTAR project

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    The Geostationary Synthetic Thinned Array Radiometer represents a promising new approach to microwave atmospheric sounding from geostationary orbit based on passive interferometry. One of the major concerns about the feasibility of this new concept is related to the ability of the sensor to cope with the failure of one or several of its single receivers/antennas. This letter shows that the inclusion of a small percentage of additional antennas significantly reduces the degradation of radiometric resolution caused by such receiver failure. Impact of antenna failure is analyzed, taking into account two test images with very different spatial harmonic content. A tradeoff analysis of several array topologies is performed so as to minimize the number of additional antennas while keeping worst case radiometric error within a reasonable level.Peer Reviewe

    On-the-fly doppler broadening of unresolved resonance region cross sections via probability band interpolation

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    In this work we present a scheme for computing temperature-dependent unresolved resonance region cross sections in Monte Carlo neutron transport simulations. This approach relies on the generation of equiprobable cross section magnitude bands on an energy-temperature mesh. The bands are then interpolated in energy and temperature to obtain a cross section value. This is in contrast to the typical procedure of pre-generating probability tables at all temperatures present in the simulation. As part of this work, a flexible probability table generation capability is integrated into the continuous-energy neutron transport code OpenMC [1]. Both single-level and multi-level Breit-Wigner formalisms are supported, as is modeling of the resonance structure of competitive reactions. A user-specified cross section band tolerance is enabled with batch statistics. Probability tables are generated for all 268 ENDF/B-VII.1 [2] isotopes that have an unresolved resonance region evaluation. Integral benchmark simulations of the Big Ten critical assembly show that, for a system that is sensitive to the unresolved resonance region, a temperature interval of ∼200 K around 293.6 K is sufficient to reproduce the keff value that is obtained with probability tables generated exactly at room temperature. A finer mesh of < 50 K is required to reproduce some cross section values at the common target relative difference of 0.1

    The Phase-Contrast Imaging Instrument at the Matter in Extreme Conditions Endstation at LCLS

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    We describe the Phase-Contrast Imaging instrument at the Matter in Extreme Conditions (MEC) endstation of the Linac Coherent Light Source. The instrument can image phenomena with a spatial resolution of a few hundreds of nanometers and at the same time reveal the atomic structure through X-ray diffraction, with a temporal resolution better than 100 femtosecond. It was specifically designed for studies relevant to High-Energy-Density Science and can monitor, e.g., shock fronts, phase transitions, or void collapses. This versatile instrument was commissioned last year and is now available to the MEC user community

    Synchronous facial action binds dynamic facial features

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    We asked how dynamic facial features are perceptually grouped. To address this question, we varied the timing of mouth movements relative to eyebrow movements, while measuring the detectability of a small temporal misalignment between a pair of oscillating eyebrows-an eyebrow wave. We found eyebrow wave detection performance was worse for synchronous movements of the eyebrows and mouth. Subsequently, we found this effect was specific to stimuli presented to the right visual field, implicating the involvement of left lateralised visual speech areas. Adaptation has been used as a tool in low-level vision to establish the presence of separable visual channels. Adaptation to moving eyebrows and mouths with various relative timings reduced eyebrow wave detection but only when the adapting mouth and eyebrows moved asynchronously. Inverting the face led to a greater reduction in detection after adaptation particularly for asynchronous facial motion at test. We conclude that synchronous motion binds dynamic facial features whereas asynchronous motion releases them, allowing adaptation to impair eyebrow wave detection

    Direct, on-the-fly calculation of unresolved resonance region cross sections in Monte Carlo simulations

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    The theory, implementation, and testing of a method for on-the-fly unresolved resonance region cross section calculations in continuous-energy Monte Carlo neutron transport codes are presented. With this method, each time that a cross section value is needed within the simulation, a realization of unresolved resonance parameters is generated about the desired energy and temperature-dependent single-level Breit-Wigner resonance cross sections are computed directly via use of the analytical ψ − χ Doppler integrals. Results indicate that, in room-temperature simulations of a system that is known to be highly sensitive to the effects of resonance structure in unresolved region cross sections, the on-the-fly treatment produces results that are in excellent agreement with those produced with the well-established probability table method. Additionally, similar agreement is observed between results obtained from the on-the-fly and probability table methods for another intermediate spectrum system at temperatures of 293.6 K and 2500 K. With relatively tight statistical uncertainties at the ∼ 10 pcm level, all on-the-fly and probability table keff eigenvalues agree to within 2σ. Also, we use the on-the-fly approach to show that accounting for the resonance structure of competitive reaction cross sections can have non-negligible effects for intermediate/fast spectrum systems. Biases of up to 90 pcm are observed. Finally, the consequences of the on-the-fly method with respect to simulation runtime and memory requirements are briefly discussed.United States. Department of Energy (Consortium for Advanced Simulation of Light Water Reactors. Contract DE-AC05-00OR22725
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