8,355 research outputs found

    Cloud Chamber: A Performance with Real Time Two-Way Interaction between Subatomic Particles and Violinist

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    ‘Cloud Chamber’ - a composition by Alexis Kirke, Antonino Chiaramonte, and Anna Troisi - is a live performance in which the invisible quantum world becomes visible as a violinist and subatomic particle tracks interact together. An electronic instrument was developed which can be “played” live by radioactive atomic particles. Electronic circuitry was developed enabling a violin to create a physical force field that directly affects the ions generated by cosmic radiation particles. This enabled the violinist and the ions to influence each other musically in real time. A glass cloud chamber was used onstage to make radioactivity visible in bright white tracks moving within, with the tracks projected onto a large screen

    Current status of MCNP6 as a simulation tool useful for space and accelerator applications

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    For the past several years, a major effort has been undertaken at Los Alamos National Laboratory (LANL) to develop the transport code MCNP6, the latest LANL Monte-Carlo transport code representing a merger and improvement of MCNP5 and MCNPX. We emphasize a description of the latest developments of MCNP6 at higher energies to improve its reliability in calculating rare-isotope production, high-energy cumulative particle production, and a gamut of reactions important for space-radiation shielding, cosmic-ray propagation, and accelerator applications. We present several examples of validation and verification of MCNP6 compared to a wide variety of intermediate- and high-energy experimental data on reactions induced by photons, mesons, nucleons, and nuclei at energies from tens of MeV to about 1 TeV/nucleon, and compare to results from other modern simulation tools.Comment: 4 pages, 3 figures, Proc. 11th Conference on the Intersections of Particle and Nuclear Physics (CIPANP 2012), St. Petersburg, FL, May 28 - June 3, 201

    Building a future-oriented science education system in New Zealand - how are we doing?

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    This paper makes the case for deep and radical change to New Zealand's approach to science education. It discusses the implications of recent science education research and policy work, and argues New Zealand still has a long way to go to developing a future-oriented science education system. It explores what needs to change and contains suggestions for some first steps

    Schrödinger's microbe: implications of coercing a living organism into a coherent quantum mechanical state

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    Consideration of the experimental activities carried out in one discipline, through the lens of another, can lead to novel insights. Here, we comment from a biological perspective upon experiments in quantum mechanics proposed by physicists that are likely to feasible in the near future. In these experiments, an entire living organism would be knowingly placed into a coherent quantum state for the first time, i.e. would be coerced into demonstrating quantum phenomena. The implications of the proposed experiment for a biologist depend to an extent upon the outcomes. If successful (i.e. quantum coherence is achieved and the organism survives after returning to a normal state), then the organism will have been temporarily in a state where it has an unmeasurable metabolism-not because a metabolic rate is undetectable, but because any attempt to measure it would automatically bring the organism out of the state. We argue that this would in essence represent a new category of cryptobiosis. Further, the organism would not necessarily retain all of the characteristics commonly attributed to living systems, unlike the currently known categories of cryptobiosis. If organisms can survive having previously been in a coherent state, then we must accept that living systems do not necessarily need to remain in a decoherent state at all times. This would be something new to biologists, even if it might seem trivial to physicists. It would have implications concerning the physical extremes organisms can tolerate, the search for extraterrestrial life, and our philosophical view of animation

    A Smirnov-Bickel-Rosenblatt theorem for compactly-supported wavelets

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    In nonparametric statistical problems, we wish to find an estimator of an unknown function f. We can split its error into bias and variance terms; Smirnov, Bickel and Rosenblatt have shown that, for a histogram or kernel estimate, the supremum norm of the variance term is asymptotically distributed as a Gumbel random variable. In the following, we prove a version of this result for estimators using compactly-supported wavelets, a popular tool in nonparametric statistics. Our result relies on an assumption on the nature of the wavelet, which must be verified by provably-good numerical approximations. We verify our assumption for Daubechies wavelets and symlets, with N = 6, ..., 20 vanishing moments; larger values of N, and other wavelet bases, are easily checked, and we conjecture that our assumption holds also in those cases

    QuizMap: Open social student modeling and adaptive navigation support with TreeMaps

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    In this paper, we present a novel approach to integrate social adaptive navigation support for self-assessment questions with an open student model using QuizMap, a TreeMap-based interface. By exposing student model in contrast to student peers and the whole class, QuizMap attempts to provide social guidance and increase student performance. The paper explains the nature of the QuizMap approach and its implementation in the context of self-assessment questions for Java programming. It also presents the design of a semester-long classroom study that we ran to evaluate QuizMap and reports the evaluation results. © 2011 Springer-Verlag Berlin Heidelberg

    Genomic variations associated with attenuation in Mycobacterium avium subsp paratuberculosis vaccine strains

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    BACKGROUND: Mycobacterium avium subspecies paratuberculosis (MAP) whole cell vaccines have been widely used tools in the control of Johne's disease in animals despite being unable to provide complete protection. Current vaccine strains derive from stocks created many decades ago; however their genotypes, underlying mechanisms and relative degree of their attenuation are largely unknown. RESULTS: Using mouse virulence studies we confirm that MAP vaccine strains 316 F, II and 2e have diverse but clearly attenuated survival and persistence characteristics compared with wild type strains. Using a pan genomic microarray we characterise the genomic variations in a panel of vaccine strains sourced from stocks spanning over 40 years of maintenance. We describe multiple genomic variations specific for individual vaccine stocks in both deletion (26-32 Kbp) and tandem duplicated (11-40 Kbp) large variable genomic islands and insertion sequence copy numbers. We show individual differences suitable for diagnostic differentiation between vaccine and wild type genotypes and provide evidence for functionality of some of the deleted MAP-specific genes and their possible relation to attenuation. CONCLUSIONS: This study shows how culture environments have influenced MAP genome diversity resulting in large tandem genomic duplications, deletions and transposable element activity. In combination with classical selective systematic subculture this has led to fixation of specific MAP genomic alterations in some vaccine strain lineages which link the resulting attenuated phenotypes with deficiencies in high reactive oxygen species handling

    Development Of An Engineered Bioluminescent Reporter Phage For Detection Of Bacterial Blight Of Crucifers

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    Bacterial blight, caused by the phytopathogen Pseudomonas cannabina pv. alisalensis, is an emerging disease afflicting important members of the Brassicaceae family. The disease is often misdiagnosed as pepper spot, a much less severe disease caused by the related pathogen Pseudomonas syringae pv. maculicola. We have developed a phage-based diagnostic that can both identify and detect the causative agent of bacterial blight and differentiate the two pathogens. A recombinant >light>-tagged reporter phage was generated by integrating bacterial luxAB genes encoding luciferase into the genome of P. cannabina pv. alisalensis phage PBSPCA1. The PBSPCA1::luxAB reporter phage is viable and stable and retains properties similar to those of the wildtype phage. PBSPCA1::luxAB rapidly and sensitively detects P. cannabina pv. alisalensis by conferring a bioluminescent signal response to cultured cells. Detection is dependent on cell viability. Other bacterial pathogens of Brassica species such as P. syringae pv. maculicola, Pseudomonas marginalis, Pectobacterium carotovorum, Xanthomonas campestris pv. campestris, and X. campestris pv. raphani either do not produce a response or produce significantly attenuated signals with the reporter phage. Importantly, the reporter phage detects P. cannabina pv. alisalensis on diseased plant specimens, indicating its potential for disease diagnosis.National Science Foundation Small Business Innovative Research 1012059U.S. Department of EducationU.S. Department of AgricultureCellular and Molecular Biolog

    Synthesis of sulfoximine propargyl carbamates under improved conditions for rhodium catalyzed carbamate transfer to sulfoxides

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    Sulfoximines provide aza-analogues of sulfones, with potentially improved properties for medicinal chemistry. The sulfoximine nitrogen also provides an additional vector for the inclusion of other functionality. Here, we report improved conditions for rhodium catalyzed synthesis of sulfoximine (and sulfilimine) carbamates, especially for previously low-yielding carbamates containing pi-functionality. Notably we report the preparation of propargyl sulfoximine carbamates to provide an alkyne as a potential click handle. Using Rh2(esp)2 as catalyst and a DOE optimization approach provided considerably increased yields
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