2,635 research outputs found

    Phase Diagrams for Sonoluminescing Bubbles

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    Sound driven gas bubbles in water can emit light pulses. This phenomenon is called sonoluminescence (SL). Two different phases of single bubble SL have been proposed: diffusively stable and diffusively unstable SL. We present phase diagrams in the gas concentration vs forcing pressure state space and also in the ambient radius vs gas concentration and vs forcing pressure state spaces. These phase diagrams are based on the thresholds for energy focusing in the bubble and two kinds of instabilities, namely (i) shape instabilities and (ii) diffusive instabilities. Stable SL only occurs in a tiny parameter window of large forcing pressure amplitude Pa1.21.5P_a \sim 1.2 - 1.5atm and low gas concentration of less than 0.4%0.4\% of the saturation. The upper concentration threshold becomes smaller with increasing forcing. Our results quantitatively agree with experimental results of Putterman's UCLA group on argon, but not on air. However, air bubbles and other gas mixtures can also successfully be treated in this approach if in addition (iii) chemical instabilities are considered. -- All statements are based on the Rayleigh-Plesset ODE approximation of the bubble dynamics, extended in an adiabatic approximation to include mass diffusion effects. This approximation is the only way to explore considerable portions of parameter space, as solving the full PDEs is numerically too expensive. Therefore, we checked the adiabatic approximation by comparison with the full numerical solution of the advection diffusion PDE and find good agreement.Comment: Phys. Fluids, in press; latex; 46 pages, 16 eps-figures, small figures tarred and gzipped and uuencoded; large ones replaced by dummies; full version can by obtained from: http://staff-www.uni-marburg.de/~lohse

    Behavioural clusters and predictors of performance during recovery from stroke

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    We examined the patterns and variability of recovery post-stroke in multiple behavioral domains. A large cohort of first time stroke patients with heterogeneous lesions was studied prospectively and longitudinally at 1-2 weeks, 3 months and one year post-injury with structural MRI to measure lesion anatomy and in-depth neuropsychological assessment. Impairment was described at all timepoints by a few clusters of correlated deficits. The time course and magnitude of recovery was similar across domains, with change scores largely proportional to the initial deficit and most recovery occurring within the first three months. Damage to specific white matter tracts produced poorer recovery over several domains: attention and superior longitudinal fasciculus II/III, language and posterior arcuate fasciculus, motor and corticospinal tract. Finally, after accounting for the severity of the initial deficit, language and visual memory recovery/outcome was worse with lower education, while the occurrence of multiple deficits negatively impacted attention recovery

    Variations in ammonium enhancement, an indication of nitrogen deficiency in New England coastal phytoplankton populations

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    Phytoplankton populations in the coastal waters of the Gulf of Maine have been tested for cellular nitrogen deficiency by adding ammonium to the dark bottle in a conventional 14C experiment. In phytoplankton cultures it has been shown that under conditions of nitrogen limitation to growth, accelerated dark fixation after ammonium addition signals the onset of cellular nitrogen deficiency...

    Gotham Skylines: The Intersection of Scènes à Faire and Fictional Facts In Comic Books, Graphic Novels, and their Derivative Works

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    In just a decade and a half since the modern superhero film exploded onto the scene, the comic books and graphic novels that have long been the very definition of a fringe or niche interest, have morphed into a multi-billion dollar film, television and video game empire. The two main players in this industry, Marvel and DC, are owned by juggernauts in the entertainment industry. More importantly, some of these characters have been around for over three-quarters of a century. Readers keyed into intellectual property law, particularly copyright, should begin to see the issue. The copyright protection on these characters will expire in the coming years, and could potentially open up a wide range of other works based on these venerable and valuable properties. While trademark law may provide some limited protections, there may in fact be another way for these characters to be protected. There are several exceptions to copyright, but the one most applicable to our case is the prohibition against recognizing copyright protection for “Scènes à Faire.” Succinctly put, the doctrine prohibits copyrighting a scene that is indispensable to conveying basic information about the overall copyrighted work. In other words, using a skyline shot of New York City to convey that a film is set in New York City is not copyrightable on its own, even though the rest of the film is certainly eligible for protection. In a similar manner, facts may not be copyrighted. However, fictional facts may be. For example, the fact that Superman was born on the planet Krypton and sent to Earth as a baby to be raised in Smallville by the Kent family are ‘facts’ of a sort, but as fictional facts they are subject to copyright protection. The world of comic books is full of hypothetical questions regarding competing forces. Can Thor’s hammer (the irresistible force) destroy Captain America’s shield (the immovable object)? Who is faster, Superman or The Flash? In this mix we bring a legal conundrum to join the debates that swarm around conventions and online message boards. What happens when fictional facts interact with scènes à faire in the manner that occurs in films based on comic books? Which wins, the protectable nature of fictional facts or the generic scenes that are bereft of protection? In this note I will argue that when fictional facts interact with scènes à faire in comic book movies, the previously unprotected scenes gain copyright protectable status. While this may seem a moot point, it is not. The extensive protections offered by copyright will enable those copyright holders to continue exploiting the vast commercial value of those rights for decades to come

    Prospects for the Measurement of the Higgs Yukawa Couplings to b and c quarks, and muons at CLIC

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    The investigation of the properties of the Higgs boson, especially a test of the predicted linear dependence of the branching ratios on the mass of the final state is going to be an integral part of the physics program at colliders at the energy frontier for the foreseeable future. The large Higgs boson production cross section at a 3TeV CLIC machine allows for a precision measurement of the Higgs branching ratios. The cross section times branching ratio of the decays H->bb, H->cc and H->{\mu}{\mu} of a Standard Model Higgs boson with a mass of 120 GeV can be measured with a statistical uncertainty of 0.23%, 3.1% and 15%, respectively, assuming an integrated luminosity of 2 ab-1.Comment: 6 pages, 4 figure

    Establishment of a minor groove binder-probe based quantitative real time PCR to detect Borrelia burgdorferi sensu lato and differentiation of Borrelia spielmanii by ospA-specific conventional PCR

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    <p>Abstract</p> <p>Background</p> <p><it>Borrelia burgdorferi </it>sensu lato (sl), the causative agent of Lyme borreliosis, is transmitted by ticks of the genus <it>Ixodes </it>as vector. For identification of <it>Borrelia </it>infections in ticks a TaqMan™ minor groove binder (MGB) probe-based quantitative real time PCR (qPCR) was established targeting the 5S-23S intergenic spacer. Extension to a duplex qPCR included an <it>Ixodes </it>spp. positive control to verify successful DNA isolation. Besides qPCR, an <it>osp</it>A-specific conventional PCR for species-specific identification of <it>B. spielmanii </it>was established. Afterwards 1000 <it>I. ricinus </it>flagged in the city of Hanover, Germany, were investigated for <it>B. burgdorferi </it>sl infections followed by species identification. Furthermore, <it>I. hexagonus </it>ticks were investigated to proof applicability of the PCRs.</p> <p>Results</p> <p>Quantitative real time PCR (qPCR) identifying <it>B. burgdorferi </it>sl in ticks was able to detect 1-10 copies per reaction. <it>B. spielmanii osp</it>A-specific conventional PCR was also highly specific and showed no cross reactions with the other tested <it>Borrelia </it>species. From 1000 hanoveranian ticks 24.3% were positive compared to only 7.4% positives by dark-field microscopy. Related to tick stage 1.7% larvae, 18.1% nymphs, and 34.6% adults were positive. The most frequent species was <it>B. garinii</it>, followed by <it>B. afzelii</it>, <it>B. spielmanii</it>, <it>B. valaisiana </it>and <it>B. burgdorferi </it>sensu stricto (ss). 70.6% of <it>I. ricinus </it>were mono-infected, whereas 28.0% and 1.4% were infected with two and three <it>Borrelia </it>species, respectively. From 232 <it>I. hexagonus </it>collected from hedgehogs in different sites of Germany, qPCR detected 5.7% to be infected with <it>B. burgdorferi </it>sl, which were identified as <it>B. afzelii</it>, <it>B. garinii </it>and <it>B. spielmanii</it>.</p> <p>Conclusions</p> <p>The evaluated qPCR to detect <it>B. burgdorferi </it>sl in <it>Ixodes </it>spp. is highly specific and sensitive. As a duplex qPCR including detection of <it>Ixodes </it>spp. DNA it is the first DNA based technique incorporating a control for successful DNA isolation from the vector tick. Establishment of a <it>B. spielmanii </it>specific conventional PCR filled the gap in PCR identification of principal European <it>Borrelia </it>genospecies. Practical application showed that all European pathogenic <it>Borrelia </it>spp. were present in <it>I. ricinus </it>flagged in recreational areas of the city of Hanover and confirmed <it>I. hexagonus </it>as reservoir for pathogenic <it>Borrelia </it>spp.</p
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