2,165 research outputs found
Reduction of dimension for nonlinear dynamical systems
We consider reduction of dimension for nonlinear dynamical systems. We
demonstrate that in some cases, one can reduce a nonlinear system of equations
into a single equation for one of the state variables, and this can be useful
for computing the solution when using a variety of analytical approaches. In
the case where this reduction is possible, we employ differential elimination
to obtain the reduced system. While analytical, the approach is algorithmic,
and is implemented in symbolic software such as {\sc MAPLE} or {\sc SageMath}.
In other cases, the reduction cannot be performed strictly in terms of
differential operators, and one obtains integro-differential operators, which
may still be useful. In either case, one can use the reduced equation to both
approximate solutions for the state variables and perform chaos diagnostics
more efficiently than could be done for the original higher-dimensional system,
as well as to construct Lyapunov functions which help in the large-time study
of the state variables. A number of chaotic and hyperchaotic dynamical systems
are used as examples in order to motivate the approach.Comment: 16 pages, no figure
Utilizing Bayesian Techniques for User Interface Intelligence
The purpose of this research is to study the injection of an intelligent agent into modern user interface technology. This agent is intended to manage the complex interactions between the software system and the user, thus making the complexities transparent to the user. The background study will show that while interesting and promising research exists in the domain of intelligent interface agents, very little research has been published that indicates true success in representing the uncertainty involved in predicting user intent. The interface agent architecture presented in this thesis will offer one solution for solving the problem using a newly developed Bayesian-based agent called the Intelligent Interface Agent (IIA). The proof of concept of this architecture has been implemented in an actual expert system, and this thesis presents the results of the implementation. The conclusions of this thesis will show the viability of this new agent architecture, as well as promising future research in examination of cognitive models, development of an intelligent interface agent interaction language, expansion of meta-level interface learning, and refinement of the PESKI user interface
The synergistic effects of elevated temperature and CO2 - induced ocean acidification reduce cardiac performance and increase disease susceptibility in subadult, female American lobsters Homarus americanus H. Milne Edwards, 1837 (Decapoda: Astacidea: Nephropidae) from the Gulf of Maine
Increased greenhouse gas emissions have caused rapid ocean warming (OW) and reduced ocean pH via acidification (OA). Both OW and OA will likely impact marine crustaceans, but they are often examined in isolation. We conducted an environmental-stressor experiment to understand how exposure to current summer conditions (16 °C, pH 8.0), OW only (20 °C, pH 8.0), OA only (16 °C, pH 7.6), or both acidification and warming, OAW (20 °C, pH 7.6), differentially influence thermal physiology and immune response of female subadults of the American lobster, Homarus americanus H. Milne Edwards, 1837. Following a 42 d exposure, cardiac performance was assessed during an acute thermal stress, and lobsters were subjected to a subsequent 21 d pathogen challenge with the bacterium Aerococcus viridans var. homari, the causative agent of gaffkemia. Lobsters under OAW had significantly lower (P ≤ 0.02) Arrhenius break temperatures (ABT), an indicator of thermal limits of capacity, compared to lobsters exposed to all other treatments, suggesting these stressors act synergistically to reduce physiological performance. Individuals from the OW and OAW treatments also had significantly lower (P ≤ 0.035) total hemocyte counts (THCs), an indicator of immune response, and showed a reduced median time to death (by up to 5 d sooner) post A. viridans injection compared to lobsters exposed to current summer conditions. Moreover, nearly twice as many lobsters exposed to OAW lost at least one claw during the pathogen challenge compared to all other treatment groups, potentially increasing the risk of mortality due to secondary infection. Together, these results suggest that OAW will impact the physiology and immune response of subadult H. americanus, potentially influencing successful recruitment to the fishery
Fault-tolerant quantum computation with high threshold in two dimensions
We present a scheme of fault-tolerant quantum computation for a local
architecture in two spatial dimensions. The error threshold is 0.75% for each
source in an error model with preparation, gate, storage and measurement
errors.Comment: 4 pages, 4 figures; v2: A single 2D layer of qubits (simple square
lattice) with nearest-neighbor translation-invariant Ising interaction
suffices. Slightly improved threshol
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County-Level Hispanic Ethnic Density and Cardiovascular Disease Mortality.
Background Hispanics are the fastest growing ethnic group in the United States, and little is known about how Hispanic ethnic population density impacts cardiovascular disease ( CVD ) mortality. Methods and Results We examined county-level deaths for Hispanics and non-Hispanic whites from 2003 to 2012 using data from the National Center for Health Statistics' Multiple Cause of Death mortality files. Counties with more than 20 Hispanic deaths (n=715) were included in the analyses. CVD deaths were identified using International Classification of Diseases, Tenth Revision (ICD-10), I00 to I78, and population estimates were calculated using linear interpolation from 2000 and 2010 census data. Multivariate linear regression was used to examine the association of Hispanic ethnic density with Hispanic and non-Hispanic white age-adjusted CVD mortality rates. County-level age-adjusted CVD mortality rates were adjusted for county-level demographic, socioeconomic, and healthcare factors. There were a total of 4Â 769Â 040 deaths among Hispanics (n=382Â 416) and non-Hispanic whites (n=4Â 386Â 624). Overall, cardiovascular age-adjusted mortality rates were higher among non-Hispanic whites compared with Hispanics (244.8 versus 189.0 per 100Â 000). Hispanic density ranged from 1% to 96% in each county. Counties in the highest compared with lowest category of Hispanic density had 60% higher Hispanic mortality (215.3 versus 134.2 per 100Â 000 population). In linear regression models, after adjusting for county-level demographic, socioeconomic, and healthcare factors, increasing Hispanic ethnic density remained strongly associated with mortality for Hispanics but not for non-Hispanic whites. Conclusions CVD mortality is higher in counties with higher Hispanic ethnic density. County-level characteristics do not fully explain the higher CVD mortality among Hispanics in ethnically concentrated counties
Maximizing Hospitality Learning Outcomes: An Integrated Experiential In-Class Approach
This study explored the influence of an experiential, in-class approach to the hospitality curriculum as a means of increasing its efficiency and effectiveness. Specifically, the study provides an example of how hospitality faculty might utilize an experiential, in-class approach to integrate additional hospitality-specific content along with process and content issues for working in teams and team decision-making. The results of this study support the efficient and effective use of an experiential inclass teaching method. The value of this study is twofold: (1) it provides an initial test of this approach’s usefulness and (2) it provides a forum for continued conversations of how experiential approaches can be utilized to enhance and reinforce other hospitality content and managerial skills and to bridge the gap between vocational and liberal education outcomes
All-fibre wavefront sensor
We report on a tapered three-core optical fibre that can be used as a
tip-tilt wavefront sensor. In this device, a coupled region of a few
millimetres at the sensing tip of the fibre converts fragile phase information
from an incoming wavefront into robust intensity information within each of the
cores. The intensity information can be easily converted to linear wavefront
error over small ranges, making it ideal for closed loop systems. The sensor
uses minimal information to infer tip-tilt and is compatible with remote
detector arrays. We explore its application within adaptive optics and present
a validation case to show its applicability to astronomy.Comment: 7 pages, 6 figure
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