630 research outputs found

    An Investigation into Animating Plant Structures within Real-time Constraints

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    This paper is an analysis of current developments in rendering botanical structures for scientic and entertainment purposes with a focus on visualising growth. The choices of practical investigations produce a novel approach for parallel parsing of difficult bracketed L-Systems, based upon the work of Lipp, Wonka and Wimmer (2010). Alongside this is a general overview of the issues involved when looking at growing systems, technical details involving programming for the Graphics Processing Unit (GPU) and other possible solutions for further work that also could achieve the project's goals

    VHEeP: A very high energy electron-proton collider based on proton-driven plasma wakefield acceleration

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    Based on current CERN infrastructure, an electron-proton collider is proposed at a centre-of-mass energy of about 9 TeV. A 7 TeV LHC bunch is used as the proton driver to create a plasma wakefield which then accelerates electrons to 3 TeV, these then colliding with the other 7 TeV LHC proton beam. The basic parameters of the collider are presented, which although of very high energy, has integrated luminosities of the order of 1 pb1^{-1}/year. For such a collider, with a centre-of-mass energy 30 times greater than HERA, parton momentum fractions, xx, down to about 10810^{-8} are accessible for Q2Q^2 of 1 GeV2^2 and could lead to effects of saturation or some other breakdown of DGLAP being observed. The total photon-proton cross section can be measured up to very high energies and also at different energies as the possibility of varying the electron beam energy is assumed; this could have synergy with cosmic-ray physics. Other physics which can be pursued at such a collider are contact interaction searches, such as quark and electron substructure, and measurements of the proton structure as well as other more conventional measurements of QCD at high energies and in a new kinematic regime. The events at very low xx will lead to electrons and the hadronic final state produced at very low angles and so a novel spectrometer device will be needed to measure these. First ideas of the physics programme of such a collider are given.Comment: 7 pages, 4 figures, presented at the DIS 2015 Workshop, Dalla

    The Effects of Vaping on Oral Streptococci and Oral Inflammation

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    E-cigarette (e-cig) use is rising, but much is unknown about the effects of its vapor. This vapor contains chemicals such as propylene glycol, a known antimicrobial, and nicotine, whose derivatives are carcinogenic. Here, we study the effects of vaping on resident bacteria of the oral cavity and on oral cell inflammation. Oral streptococci are major residents in the oral cavity, with S. mutans the primary cause of dental caries. Growth and biofilm formation have been shown to be enhanced upon exposure to traditional cigarette smoke in vitro. In this study, we analyzed the effects of e-cig vapor on growth and biofilm formation in S. mutans, S. sanguinis, and S. gordonii. Organisms and oral epithelial cells were treated using nicotine-free and 3mg nicotine vapor, as well as double-shot menthol freeze flavored 3mg nicotine vapor in a vape chamber designed to phenocopy physiologically relevant exposure. Nicotine-independent inhibition of growth occurred upon exposure in all three bacterial species. Interestingly, biofilm formation was enhanced in the S. mutans while decreased in S. sanguinis and S. gordonii. Epithelial cells showed activation of survival pathways by Western Blot upon exposure to only e-cigarette vapor as well as co-culturing of bacterial and oral epithelial cells at a multiplicity of infection of one The pioneer colonizers S. gordonii and S. sanguinis generally antagonize caries-causing S. mutans, which can become a predominant member of the community under appropriate conditions, leading to dental caries formation. The observed decrease in the biofilm formation of the commensals S. sanguinis and S. gordonii upon e-cig vapor exposure indicates the opportunistic colonization of S. mutans, whose biofilm-forming abilities increased. Following e-cig usage, dental caries and cancer in the oral epithelium may result from this dysbiosis of the microbiome

    ESTIMATING WOLF PREDATION METRICS, PATTERNS, AND DYNAMICS ACROSS TIME AND SPACE IN THE MULTI-PREY SYSTEM OF YELLOWSTONE NATIONAL PARK

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    Predation is a fundamental driver in ecology, structuring ecosystems across the globe. However, understanding the effects of large carnivore predation is limited by both the observation process and the shorter duration of many studies. I used data from 23 years in Yellowstone National Park to disentangle both the importance of wolf predation on prey, and the imperfect observation process of studying predation. I first used field observations to test whether a sexually-selected trait, antlers in male elk, deterred wolf predation. I found that antlers reduced predation risk, emphasizing the selective nature of predation. Next, I used GPS data and ground-based observations to develop wolf sightability models to understand the nature of wolf sightings. I found forest cover, distance from road, topography, and wolf group size affected the probability of observing wolves. Next, I leveraged my sightability model to develop a Bayesian markrecapture abundance model that estimated the number of ungulates fed on by wolf packs during study sessions. I built a model for carcass detection by ground-based observation, aerial-based observation, and GPS cluster searches. Overlooking all details, field methods found only 47% of the estimated occasions when wolf packs fed on ungulates. Using these detection-corrected estimates to evaluate how six wolf predation metrics differed through time as elk declined and stabilized and bison increased, I found that wolf predation on elk generally declined concurrent with the elk decline. I also found that wolf diet (niche) breadth expanded over time primarily by scavenging bison. Though generalizing was challenging, using the simple metric of predation rate, I found predation rate was inversely density dependent in winter on just the wintering elk population within northern Yellowstone National Park. However, wolf predation was conversely a stabilizing force when considering annual predation rate on the entire northern Yellowstone elk population. These observations are consistent with wolves acting as a stabilizing, regulating force on the northern Yellowstone elk population. Finally, I built theoretical models guided by my observations of the wolf-elk-bison system in northern Yellowstone to evaluate how scavenging affects predator-prey dynamics. I found that including scavenging fundamentally changes dynamics, generally increasing prey and predator populations

    A compact electron injector for the EIC based on plasma wakefields driven by the RHIC-EIC proton beam

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    Initial simulations investigating using the RHIC-EIC proton beam as the drive beam in a plasma wakefield acceleration experiment are presented. The proton beam enters the plasma and undergoes self-modulation, forming a series of microbunches. These microbunches resonantly drive electron density perturbations within the plasma, exciting a longitudinal electric field with accelerating gradients in excess of GVm1\mathrm{GVm^{-1}}. Injecting electrons into the resulting wakefield offers an efficient method for accelerating electron bunches for use in the proposed EIC collider.Comment: 6 pages, 3 figures, submitted as proceedings for the XXVII International Workshop on Deep-Inelastic Scattering and Related Subjects (DIS2019

    The microbial metabolism of benzene and crude oil under diverse anaerobic conditions.

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    The research reported here expands the range of knowledge for anaerobic hydrocarbon metabolism, as well as provides a sound foundation for the microbial destruction of compounds once thought to be completely recalcitrant under anaerobic conditions.Using inocula from a variety of anoxic environments that varied in exposure, extent of hydrocarbon contamination and redox potential, studies were undertaken to examine the prospective for the microbial degradation of benzene under strictly anaerobic conditions. Results indicated that when chronically hydrocarbon-contaminated sediments were used as a source of inoculum, the anaerobic degradation of benzene under sulfate-reducing, Fe(III)-reducing and methanogenic conditions was achievable. Confirmation of benzene mineralization was accomplished by the recovery of 14CO2 from radiolabeled benzene in sulfate- and Fe(III)-reducing incubations, and the recovery of 14CO2 and 14CH4 in methanogenic incubations. The latter finding was the first confirmation of benzene degradation with carbon dioxide serving as the terminal electron acceptor.Benzene is the simplest aromatic hydrocarbon, yet poses one of the greatest environmental health risks due to its high water solubility and the fact that it is a known carcinogen. Often times benzene is introduced into the subsurface due to spillage or the leaking of gasoline from underground storage tanks. The large influx of carbon often results in the depletion of oxygen reserves due to heterotrophic respiration during metabolism of the more labile compounds thereby producing anoxic conditions. Thus, the metabolic fate of benzene in anaerobic environments has come under intense scrutiny.Further examination of the metabolic fate of benzene in each of these microbial enrichments indicated the appearance of phenol and benzoate as putative intermediates. Using 13C-benzene as a starting material, 13C-phenol and 13C-benzoate were detected during the course of degradation under sulfate-reducing conditions. Further, 13C-phenol was also detected in Fe(III)-reducing and methanogenic enrichments, however no evidence for labeled benzoate was obtained. Nonetheless, these findings are the first to confirm the importance of benzoate as an intermediate during anaerobic benzene decay.To further investigate the susceptibility of hydrocarbons to anaerobic decay, experiments were carried out in which chronically petroleum-contaminated marine sediments were amended with an artificially weathered crude oil. Under sulfate-reducing conditions, the results obtained indicated an almost complete loss of n-alkanes from the oil within 201 days of incubation. The mineralization of alkanes was confirmed using 14C-14,15-octacosane (C28H58) with greater than 97% of the amended radioactivity recovered as 14CO2. The degradation of n-alkanes from C15 to C34 in length, extend the range of straight chain aliphatic compounds known to be amenable to anaerobic biodegradation. Further, these results indicate that the extensive alteration of n-alkanes can no longer be considered a defining characteristic of aerobic oil biodegradation processes alone
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