19,347 research outputs found

    ILR Impact Brief – Supervisor Support, Employee Control Help NYC Firefighters Cope with 9/11

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    Although individuals often work in groups and groups function within a larger environment, researchers have rarely examined the effect of context on employees’ emotions, attitudes, or behaviors. This study uses the World Trade Center attack to generate and test a context theory concerning the impact on first responders of their involvement in a catastrophic event. The model details the way in which the climate (support from supervisors and employee control over the work environment) within discrete engine and ladder companies (work units) moderates the relationship between emergency response to the attack (the stressor) and the resulting emotional strain on the firefighters. Prior studies have shown that people’s exposure to critical incidents is associated with depression, anxiety, and stress that may begin immediately or surface months later. The severity of individual reactions varies and researchers have proposed several explanatory theories, including biological and psychological factors, the way people mentally process their experiences, and the array of physical and social/emotional resources at their disposal. The authors here draw on the latter two theoretical frameworks to formulate and test several hypotheses that help explain why New York City firefighters involved in 9/11 felt more or less emotionally wrought 18 months after the attack

    Microscale application of column theory for high resolution force and displacement sensing

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    We present the design, fabrication and experimental validation of a novel device that exploits the amplification of displacement and attenuation of structural stiffness in the post-buckling deformation of slender columns to obtain pico-Newton force and nanometer displacement resolution even under an optical microscope. The extremely small size, purely mechanical sensing scheme and vacuum compatibility of the instrument makes it compatible with existing visualization tools of nanotechnology. The instrument has a wide variety of potential applications ranging from electro-mechanical characterization of one dimensional solids to single biological cells

    The Hymenopterous Parasites Agathis Pumila (Braconidae) and Epilampsis Laricinellae (Eulophidae) on the Larch Casebearer (Lepidoptera: Coleophoridae) in the Northern Lake States

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    Excerpt: The larch casebearer Coleophora laricella (Hübner) is a defoliator of larch (Larix spp.). The insect was introduced into North America from Europe at some time prior to 1886, and since has spread steadily westward. It was causing heavy defoliation by the early 1920\u27s near Ann Arbor in southern Michigan and was recorded in northeast Wisconsin in 1939, at Sault Ste. Marie, Ontario in 1942, and Port Arthur, Ontario in 1947. Many native parasites attack the case bearer but seem to effect little control. Parasites were imported from Europe beginning in 1928, but the first attempts to establish them were unsuccessful. In 1932, the United States Bureau of Entomology and Plant Quarantine made releases of Agathis pumila (Ratz.) at Lynwood, Massachusetts, and Epilampsis laricinellae (Ratz.) in Lunenburg Township, Massachusetts. These two species were successfully established

    The UV photochemistry of C2N2

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    The absorption, emission, and photodissociation yield spectra of C2N2 were measured in the 220 and 210 nm region near the 4(0)1 and 1(0)1 4(0)1 bands of the A 1 sigma + from the X 1 sigma + system. The emission spectrum showed very few lines which appeared in the absorption spectrum. Moreover, the emission had 660 ns lifetime and, at 210 nm a very large electronic emission quenching rate. Laser induced fluorescence was used to measure the relative yield of CN radicals as a function of photolysis wavelength. This spectrum seemed to follow the absorption spectrum below the dissociation threshold. Energy in the CN fragments appeared to be statistically distributed

    The heat of formation of CN radicals and radiative lifetimes of the A 1 Sigma - state of C2N2

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    Radiative lifetimes have been measured for the stable vibrational levels of the A 1 sigma - electronic state of C2N2. They range from 1.3 microsec for the 4(sub 0)(sup 1) level to 0.66 microsec for the 1(sub 0)(sup 1) 4(sub 0)(sup 1) level and in general decrease with increasing vibrational excitation. Self-quenching rate constants range from gas kinetic to ten times that. Foreign gas quenching rates are slower. Observation of emission from the 1(sub 0)(sup 1) 4(sub 0)(sup 1) level sets a lower limit for the heat of formation of CN of 439.11 kJ/mol

    SU(2) approach to the pseudogap phase of high-temperature superconductors: electronic spectral functions

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    We use an SU(2) mean-field theory approach with input from variational wavefunctions of the t-J model to study the electronic spectra in the pseudogap phase of cuprates. In our model, the high-temperature state of underdoped cuprates is realized by classical fluctuations of the order parameter between the d-wave superconductor and the staggered-flux state. Spectral functions of the intermediate and the averaged states are computed and analyzed. Our model predicts a photoemission spectrum with an asymmetric gap structure interpolating between the superconducting gap centered at the Fermi energy and the asymmetric staggered-flux gap. This asymmetry of the gap changes sign at the point where the Fermi surface crosses the diagonal (\pi,0)-(0,\pi).Comment: 7 pages, 10 figures; estimate of applicable temperature range corrected and refs. added, ref. to ARPES paper added; minor changes to published versio

    Accurate 3D Cell Segmentation using Deep Feature and CRF Refinement

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    We consider the problem of accurately identifying cell boundaries and labeling individual cells in confocal microscopy images, specifically, 3D image stacks of cells with tagged cell membranes. Precise identification of cell boundaries, their shapes, and quantifying inter-cellular space leads to a better understanding of cell morphogenesis. Towards this, we outline a cell segmentation method that uses a deep neural network architecture to extract a confidence map of cell boundaries, followed by a 3D watershed algorithm and a final refinement using a conditional random field. In addition to improving the accuracy of segmentation compared to other state-of-the-art methods, the proposed approach also generalizes well to different datasets without the need to retrain the network for each dataset. Detailed experimental results are provided, and the source code is available on GitHub.Comment: 5 pages, 5 figures, 3 table

    Development of an adaptive window-opening algorithm to predict the thermal comfort, energy use and overheating in buildings

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    This investigation of the window opening data from extensive field surveys in UK office buildings demonstrates: 1) how people control the indoor environment by opening windows; 2) the cooling potential of opening windows; and 3) the use of an ‘adaptive algorithm’ for predicting window opening behaviour for thermal simulation in ESP-r. It was found that when the window was open the mean indoor and outdoor temperatures were higher than when closed, but show that nonetheless there was a useful cooling effect from opening a window. The adaptive algorithm for window opening behaviour was then used in thermal simulation studies for some typical office designs. The thermal simulation results were in general agreement with the findings of the field surveys. The adaptive algorithm is shown to provide insights not available using non adaptive simulation methods and can assist in achieving more comfortable, lower energy buildings while avoiding overheating
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