1,953 research outputs found

    The Juxtaposition of the Ridiculous and the Sublime in Martianus Capella

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    The Changing Face of Head and Neck Cancer in the 21st Century: The Impact of HPV on the Epidemiology and Pathology of Oral Cancer

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    The longstanding notion that head and neck squamous cell carcinoma (HNSCC) is a uniform disease process is changing. Divergence in epidemiologic trends among HNSCCs arising in different anatomic subsites has introduced a view that HNSCC is a heterogeneous group. Analysis of molecular genetic changes discloses not just individual tumor differences, but also consistent large-scale differences that permit the recognition of important tumor subtypes. One recently recognized subtype is the human papillomavirus (HPV)-positive oropharyngeal carcinoma. HPV-positive oropharyngeal cancer now dominates the head and neck oncology landscape, and its escalating incidence is impacting on diagnostic, preventive and therapeutic practices

    Code Generation = A* + BURS

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    A system called BURS that is based on term rewrite systems and a search algorithm A* are combined to produce a code generator that generates optimal code. The theory underlying BURS is re-developed, formalised and explained in this work. The search algorithm uses a cost heuristic that is derived from the termrewrite system to direct the search. The advantage of using a search algorithm is that we need to compute only those costs that may be part of an optimal rewrite sequence

    Magnetomotive drive and detection of clamped-clamped mechanical resonators in water

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    We demonstrate magnetomotive drive and detection of doubly clamped string resonators in water. A compact 1.9 T permanent magnet is used to detect the fundamental and higher flexural modes of 200Ī¼m\mathrm{200 \mu m} long resonators. Good agreement is found between the magnetomotive measurements and optical measurements performed on the same resonator. The magnetomotive detection scheme can be used to simultaneously drive and detect multiple sensors or scanning probes in viscous fluids without alignment of detector beams.Comment: 4 pages, 3 figure

    Nonlinear modal interactions in clamped-clamped mechanical resonators

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    A theoretical and experimental investigation is presented on the intermodal coupling between the flexural vibration modes of a single clamped-clamped beam. Nonlinear coupling allows an arbitrary flexural mode to be used as a self-detector for the amplitude of another mode, presenting a method to measure the energy stored in a specific resonance mode. Experimentally observed complex nonlinear dynamics of the coupled modes are quantitatively captured by a model which couples the modes via the beam extension; the same mechanism is responsible for the well-known Duffing nonlinearity in clamped-clamped beams.Comment: 5 pages, 3 figure

    Getting to know you: Accuracy and error in judgments of character

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    Character judgments play an important role in our everyday lives. However, decades of empirical research on trait attribution suggest that the cognitive processes that generate these judgments are prone to a number of biases and cognitive distortions. This gives rise to a skeptical worry about the epistemic foundations of everyday characterological beliefs that has deeply disturbing and alienating consequences. In this paper, I argue that this skeptical worry is misplaced: under the appropriate informational conditions, our everyday character-trait judgments are in fact quite trustworthy. I then propose a mindreading-based model of the socio-cognitive processes underlying trait attribution that explains both why these judgments are initially unreliable, and how they eventually become more accurate

    Interactions between directly and parametrically driven vibration modes in a micromechanical resonator

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    The interactions between parametrically and directly driven vibration modes of a clamped-clamped beam resonator are studied. An integrated piezoelectric transducer is used for direct and parametric excitation. First, the parametric amplification and oscillation of a single mode are analyzed by the power and phase dependence below and above the threshold for parametric oscillation. Then, the motion of a parametrically driven mode is detected by the induced change in resonance frequency in another mode of the same resonator. The resonance frequency shift is the result of the nonlinear coupling between the modes by the displacement-induced tension in the beam. These nonlinear modal interactions result in the quadratic relation between the resonance frequency of one mode and the amplitude of another mode. The amplitude of a parametrically oscillating mode depends on the square root of the pump frequency. Combining these dependencies yields a linear relation between the resonance frequency of the directly driven mode and the frequency of the parametrically oscillating mode.Comment: 5 pages, 4 figure

    Q-factor control of a microcantilever by mechanical sideband excitation

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    We demonstrate the coupling between the fundamental and second flexural mode of a microcantilever. A mechanical analogue of cavity-optomechanics is then employed, where the mechanical cavity is formed by the second vibrational mode of the same cantilever, coupled to the fundamental mode via the geometric nonlinearity. By exciting the cantilever at the sum and difference frequencies between fundamental and second flexural mode, the motion of the fundamental mode of the cantilever is amplified and damped. This concept makes it possible to enhance or suppress the Q-factor over a wide range.Comment: 9 pages, 3 figure
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