Smooth pursuit eye movements allow primates to keep gaze pointed at small objects moving across stationary surroundings. In monkeys trained to track a small moving target, we have injected brief perturbations of target motion under different initial conditions as probes to read out the state of the visuo-motor pathways that guide pursuit. A large eye movement response was evoked if the perturbation was applied to a moving target the monkey was tracking. A small response was evoked if the same perturbation was applied to a stationary target the monkey was fixating. The gain of the response to the perturbation increased as a function of the initial speed of target motion and as a function of the interval from the onset of target motion to the time of the perturbation. The response to the perturbation also was direction selective. Gain was largest if the perturbation was along the axis of ongoing target motion and smallest if the perturbation was orthogonal to the axis of target motion. We suggest that two parallel sets of visual motion pathways through the extrastriate visual cortex may mediate, respectively, the visuo-motor processing for pursuit and the modulation of the gain of transmission through those pathways.
We present the first experimental demonstration of a fully electronic system for the temporal magnification of signals in the ultra-wideband regime. The system employs a broadband analog multiplier and uses chirped electromagnetic-bandgap structures in microstrip technology to provide the required signal dispersion. The demonstrated system achieves a time-magnification factor of five in operation on a 0.6-ns time-windowed input signal with up to 8-GHz bandwidth. We discuss the advantages and limitations of this technique in comparison to recent demonstrations involving optical components.
New melanoma therapies have shifted the expectations of patients and providers. Evaluating the impact of treatment characteristics may enhance shared decision making. A survey, including a discrete choice experiment, was utilized to evaluate perceived trade-offs of different melanoma treatments and to estimate out-of-pocket (OOP) willingness-to-pay (WTP) thresholds (January 2016 to March 2016). Participants included patients with melanoma at Huntsman Cancer Institute and their cancer care providers. Stakeholder focus groups were conducted to identify treatment attributes. Descriptive and comparative statistics and multinomial logit model were used to evaluate responses. Response rates were 41.9% (N = 220) for patients and 37.7% (N = 20) for providers. Immunotherapy and targeted therapy attributes considered important by participants were overall survival, immunotherapyrelated side effects, and skin toxicities. Patients and providers had significantly different views of quality-of-life expectations, anxiety toward melanoma, trust to make treatment decisions, sharing concerns about treatment, time to discuss treatment, understanding OOP costs, and willingness to undergo/recommend treatment (half of the patients would undergo treatment if it was effective for > 24 months). Among patients, the average monthly OOP WTP for
We present the design of a flexible multilayer circuit board for use in a custom-built microwave system for breast health monitoring. The flexible circuit features both an integrated solid-state switching network and 16 wideband antennas, which transmit short-duration pulses into the breast tissues and receive the backscattered responses. By integrating the switching matrix and the antenna array on the same substrate, we reduce the overall cost and size of the system in comparison with previously demonstrated systems in the literature. We characterize the performance of the flexible circuit board using our clinically tested experimental system and demonstrate its functionality through successful imaging of dielectrically realistic breast phantoms that simulate the presence of a tumor. This represents a step toward a more patient-friendly, compact, cost-effective, and wearable design in contrast to previous systems in the literature that required a clinical table or used bulky rigid antenna housings and electromechanical switching networks. Emily Porter (S'11) received the B.Eng. and M.Eng. degrees in electrical engineering from McGill University, Montreal, QC, Canada, in 2009 and 2010, respectively, where she is currently pursuing the Ph.D. degree in electrical engineering.She is involved in research on applied and computational electromagnetics. Her current research interests include the medical applications of microwaves, flexible antennas, the design of realistic breast phantoms and models, and the development of a wearable prototype for breast health monitoring using microwave radar.
Abstract-We experimentally demonstrate a low-cost hardware technique for synthesizing a specific electromagnetic pulse shape to improve a time-domain microwave breast imaging system. A synthesized broadband reflector (SBR) filter structure is used to reshape a generic impulse to create an ad-hoc pulse with a specifically chosen frequency spectrum that improves the detection and imaging capabilities of our experimental system. The tailored pulse shape benefits the system by improving the level of signal detection after transmission through the breast and thus permits higher-resolution images. We report on our ability to use this technique to detect the presence of tumours in realistic breast phantoms composed of varying quantities of glandular tissue. Additionally, we provide a set of images based on this experimental data that demonstrates the increased effectiveness of the system using the SBR-shaped pulse in the localisation and identification of the embedded tumour.
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