2,785 research outputs found

    A Preservative-Free Emergent Trap for the Isotopic and Elemental Analysis of Emergent Insects From a Wetland System

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    This study reports a cost-effective, live emergent trap designed for the preservative-free use in both biogeochemical and ecological analyses of emerging insects. The trap proved to be advantageous in several ways. First, the simple design made the trap time-efficient since it was easy to set-up, change, and maintain. Second, live sampling not only provided uncontaminated organisms for elemental and stable isotopic analyses, it minimized disfigurement. This resulted in rapid and easy handling, as well as identification, of adult insects. Finally, trap avoidance by ephemeropterans and odonates, a common problem encountered in the literature, was minimal and organisms from both insect orders were successfully collected

    Parity violation and the mean field approximation for the anyon gas

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    We examine an approach to justifying the mean field approximation for the anyon gas, using the scattering of anyons. Parity violation permits a nonzero average scattering angle, from which one can extract a mean radius of curvature for anyons. If this is larger than the interparticle separation, one expects that the graininess of the statistical magnetic field is unimportant, and that the mean field approximation is good. We argue that a non-conventional interaction between anyons is crucial, in which case the criterion for validity of the approximation is identical to the one deduced using a self-consistency argument.Comment: 11 pages, UdeM-LPN-TH-13

    Tunneling decay of false domain walls: the silence of the lambs

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    We study the decay of "false” domain walls, which are metastable states of the quantum theory where the true vacuum is trapped inside the wall, with the false vacuum outside. We consider a theory with two scalar fields, a shepherd field and a field of sheep. The shepherd field serves to herd the solitons of the sheep field so that they are nicely bunched together. However, quantum tunnelling of the shepherd field releases the sheep to spread out uncontrollably. We show how to calculate the tunnelling amplitude for such a disintegration

    Lattice QCD Application Development within the US DOE Exascale Computing Project

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    In October, 2016, the US Department of Energy launched the Exascale Computing Project, which aims to deploy exascale computing resources for science and engineering in the early 2020's. The project brings together application teams, software developers, and hardware vendors in order to realize this goal. Lattice QCD is one of the applications. Members of the US lattice gauge theory community with significant collaborators abroad are developing algorithms and software for exascale lattice QCD calculations. We give a short description of the project, our activities, and our plans.Comment: 35th International Symposium on Lattice Field Theory (Lattice 2017

    Gill Ventilation Rates of Mayfly Nymphs (Ephemeroptera: Heptageniidae) as a Biomonitoring Technique

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    Gill ventilation frequency (GVF) of the mayfly nymph Stenacron interpunctatum (Ephemeroptera: Heptageniidae) was studied to assess the applicability of a relatively simple, real time video methodology and to assess the potential of GVF rates for use in a chronic assay of sediment pore water. Stenacron interpunctatum nymphs were exposed to pore water samples taken along a transect from the mouth of the Fox River to Sturgeon Bay in the Green Bay area of Lake Michigan. This transect has previously been shown to exhibit several distinct gradients in sediment and water column conditions with distance from the Fox River. The highest GVF value of 6.68 ± 0.27 Hz was observed in pore water from the more polluted area near the Fox River. A lower GVF value of 5.44 ± 0.32 Hz was observed in pore water from the station near Sturgeon Bay and of 4.25 ± 0.27 Hz from the cleaner Lake Michigan station. GVF values exhibited a decreasing trend with relative distance from the mouth of the Fox River (r2 = 0.76)

    Alchemical Sensing: Creating an Embodied Experience of the Unseen Organism

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    This paper presents the research surrounding the audiovisual installation, Stars Beneath our Feet (2015) by Louise Mackenzie. It introduces the concept of alchemical sensing to describe the layered use of scientific technology in the context of an audio-visual art installation as an alternative frame of reference that attempts an embodied understanding of the unseen organism. The process of translation through layers of technology is considered as alchemical in reference to the ancient Greek and Egyptian origins of the tradition. Not alchemical in the sense of seeking immortality or turning metal into gold, but alchemical in the anima mundi sense of seeking out the ‘essence’ of matter. Referencing the development of the field of sonification, the acoustic artwork of Joe Davis and Katie Egan and of Anne Niemetz and Andrew Pelling, the use of Atomic Force Microscopy, Python, Photosounder and MAX MSP were employed to construct an embodied audio sense of the micro-organism, Dunaliella salina. Movements detected were translated using both sonification and audification techniques into sound files that were used to form the audio component of Stars Beneath Our Feet: an installation as part of Lumiere Durham 2015, a four- day international light festival produced in the UK by Artichoke. The video component of the installation was made using a combination of dark field microscopy and DSLR camera to produce moving images that focus on a perspective of micro-organisms that is other to that commonly used within scientific research. The objective of ‘looking at’ the organisms in this expanded manner and ‘listening to’ the sounds of data obtained via technological interpretation of the movement of micro- organisms in the context of an art installation adds a broader sensory dimension to our understanding of the unseen organism, one which encompasses their being in the world without consideration of their use as resources. https://vimeo.com/14712064
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