1,958 research outputs found
The Changing Face of Head and Neck Cancer in the 21st Century: The Impact of HPV on the Epidemiology and Pathology of Oral Cancer
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
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
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 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
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
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
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
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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