3,749 research outputs found
Transformation Optics scheme for two-dimensional materials
Two dimensional optical materials, such as graphene can be characterized by a
surface conductivity. So far, the transformation optics schemes have focused on
three dimensional properties such as permittivity and permeability
. In this paper, we use a scheme for transforming surface currents to
highlight that the surface conductivity transforms in a way different from
and . We use this surface conductivity transformation to
demonstrate an example problem of reducing scattering of plasmon mode from
sharp protrusions in graphene
Global disease monitoring and forecasting with Wikipedia
Infectious disease is a leading threat to public health, economic stability,
and other key social structures. Efforts to mitigate these impacts depend on
accurate and timely monitoring to measure the risk and progress of disease.
Traditional, biologically-focused monitoring techniques are accurate but costly
and slow; in response, new techniques based on social internet data such as
social media and search queries are emerging. These efforts are promising, but
important challenges in the areas of scientific peer review, breadth of
diseases and countries, and forecasting hamper their operational usefulness.
We examine a freely available, open data source for this use: access logs
from the online encyclopedia Wikipedia. Using linear models, language as a
proxy for location, and a systematic yet simple article selection procedure, we
tested 14 location-disease combinations and demonstrate that these data
feasibly support an approach that overcomes these challenges. Specifically, our
proof-of-concept yields models with up to 0.92, forecasting value up to
the 28 days tested, and several pairs of models similar enough to suggest that
transferring models from one location to another without re-training is
feasible.
Based on these preliminary results, we close with a research agenda designed
to overcome these challenges and produce a disease monitoring and forecasting
system that is significantly more effective, robust, and globally comprehensive
than the current state of the art.Comment: 27 pages; 4 figures; 4 tables. Version 2: Cite McIver & Brownstein
and adjust novelty claims accordingly; revise title; various revisions for
clarit
Photon Emission Rate Engineering using Graphene Nanodisc Cavities
In this work, we present a systematic study of the plasmon modes in a system
of vertically stacked pair of graphene discs. Quasistatic approximation is used
to model the eigenmodes of the system. Eigen-response theory is employed to
explain the spatial dependence of the coupling between the plasmon modes and a
quantum emitter. These results show a good match between the semi-analytical
calculation and full-wave simulations. Secondly, we have shown that it is
possible to engineer the decay rates of a quantum emitter placed inside and
near this cavity, using Fermi level tuning, via gate voltages and variation of
emitter location and polarization. We highlighted that by coupling to the
bright plasmon mode, the radiative efficiency of the emitter can be enhanced
compared to the single graphene disc case, whereas the dark plasmon mode
suppresses the radiative efficiency
Hero-X: Emerson Air Flow Design Challenge
This report will follow the development cycle as Capstone Team 12 solves the Emerson Airflow Problem. The problem was proposed by Emerson on HeroX: Incentive Competition, Challenges and Prizes forum. This problem is an open competition to any inventors who can solve the dilemma of measuring total air flow in a residential heating, ventilation and cooling system (HVAC). The solutions will be judged against a rubric given by Emerson that includes price-point, accuracy, scalability, ease of installation and ease of use in order of greatest to least importance [5]. The following report outlines the engineering process from interpreting the problem statement up to a proof of concept design. Each section will speak to a critical engineering consideration such as project planning, patent research, cost analysis, evaluation of competition, and design characteristics which lead to the final designs. In the final pages, two carefully designed products which solve the problem statement will be laid out in detail. The first design is a fan matrix which adjusts to fit in any units filter cavity for a non-intrusive reading at the source. The second is small pressure sensor which will traverse a duct and generate a velocity profile for a specific point in the system. Using a simple algorithm, it will determine average velocity in the section. Beyond this report, the team will further prototype and propose the solutions to Emerson by the submission deadline of January 25, 2016
Phase Angle Adaptation to Exercise Training in Cancer Patients Undergoing Treatment
Phase angle is a measure of cellular resistance and reactance to bioelectrical impedance analysis. This measurement is useful as a marker of cell membrane integrity and is used as a prognostic marker in several clinical populations. Cancer and its related treatments impact cell membrane integrity, leading to poor cell function. Exercise is shown to increase phase angle, resulting in lowered risk of hospitalization and cardiovascular events. However, the effect of chronic exercise training on phase angle in the cancer population is unclear. Purpose: To assess the effect of chronic exercise on phase angle in cancer patients who are actively undergoing chemotherapy and/or radiation. Methods: A total of 56 cancer patients who were actively undergoing chemotherapy and/or radiotherapy were recruited to participate in a 12 week exercise-based rehabilitation program at the University of Northern Colorado Cancer Rehabilitation Institute. Each participant underwent an initial assessment of physiological parameters, including body composition and phase angle analysis. Results of this assessment were used to develop an individualized exercise prescription. Each participant received prescribed, supervised, one-on-one training from a Clinical Cancer Exercise Specialist, three times per week for one hour each session. After 12 weeks, each participant underwent a follow-up assessment of physiological parameters. Results: After 12 weeks of exercise training, significant increases in whole body (Initial: 4.55 ± 0.72, Follow-up: 4.68 ± 0.68; p = 0.02), right arm (Initial: 4.45 ± 0.76, Follow-up: 4.57 ± 0.72; p = 0.03), and left arm (Initial: 4.28 ± 0.79, Follow-up: 4.39 ± 0.75; p = 0.03) phase angle was observed. Conclusion: This study demonstrates that prescribed exercise training can increase phase angle in cancer survivors even while undergoing chemotherapy and/or radiation treatments. These changes may provide insight into the protective and rehabilitative benefits (e.g., cellular health, membrane integrity, disease risk) that exercise may have in this population
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