3,076 research outputs found
Human operator modeling, joystick input notch filtering, and safety constraint enforcement for powered wheelchair operation under Parkinson’s tremor
This study considers use of a notch filter and enforcement of performance safety limits to mitigate the effects of Parkinson tremors on a battery powered wheelchair directed by a joystick. The wheelchair has regenerative braking to extend range of operation between charges. Regenerative braking transforms the wheelchair model into an autonomously switched hybrid system. The wheelchair is represented as a joystick controlled wheeled mobile robot having two modes of operation per drive wheel, propelling and regenerative braking. In this study, a Parkinson’s patient is directed to follow a path that includes moving from a stopped position to a trajectory along a wall that includes a 90˚ corner. A cognitive model of a human operator is incorporated for simulation of an operator with Parkinson’s tremor. The human operator model output provides the joystick with noisy velocity, orientation, and position commands. The article delineates a notch filter to remove the main Parkinson’s tremor from the joystick input followed by the application of velocity and acceleration performance safety limits. Results show significant feasible advantages for safe wheelchair operation by Parkinson’s patients with tremor
Introduction
The representations and interpretations of knowledge are crucial to the pursuit of science. They are not only central to education and the communication of the subject matter but also to the practice and evolution of the subjects. Furthermore, as there is still no single all-pervading approach to science so there is no single way of communication within or between emerging areas of knowledge. Maybe we could be reminded of the comments of two notable twentieth century scientists on this subject
Little Butterfly (Give Your Heart To Me)
With Ukulele arrangement. Contains advertisements and/or short musical examples of pieces being sold by publisher.https://digitalcommons.library.umaine.edu/mmb-vp/7093/thumbnail.jp
Interpreting, Representing and Integrating Scientific Knowledge from Interdisciplinary Projects
We describe a coherent, eclectic approach to interpreting, representing, and integrating knowledge from different scientific disciplines or communities of practice. The approach, called ECLECTIC, draws from a complementary blend of ethnological methods, the hermeneutic analysis of domains, and ecology. Our description focuses on the conceptual bases of this approach, its value, and uses, particularly in handling the methodological considerations in the overlapping phases of interpretation, representation, and integration. We give examples from our use of the approach and describe how it handles difficult methodological issues: (1) knowing what questions to initially ask of members of science communities, (2) identifying their states of knowledge, (3) determining the analyst’s role, (4) determining how the knowledge may be self elicited by the members themselves, (5) verifying that the interpretation and representation of the knowledge is meaningful to the members, and (6) integrating differing representations from the communities
Structure strategy interventions: Increasing reading comprehension of expository text
In this review of the literature we examine empirical studies designed to teach the structure strategy to increase reading comprehension of expository texts. First, we review the research that has served as a foundation for many of the studies examining the effects of text structure instruction. Text structures generally can be grouped into six categories: comparison, problem-and solution, causation, sequence, collection, and description. Next, we provide a historical look at research of structure strategyinterventions. Strategy interventions employ modeling, practice, and feedback to teach students how to use text structure strategically and eventually automatically. Finally, we review recent text structure interventions for elementary school students. We present similarities and differences among these studies and applications for instruction. Our review of intervention research suggests that direct instruction, modeling, scaffolding, elaborated feedback, and adaptation of instruction to student performance are keys in teaching students to strategically use knowledge about text structure
Symmetries of CMB Temperature Correlation at Large Angular Separations
A new analysis is presented of the angular correlation function
of cosmic microwave background (CMB) temperature at large angular separation,
based on published maps derived from {\sl WMAP} and {\sl Planck} satellite
data, using different models of astrophysical foregrounds. It is found that
using a common analysis, the results from the two satellites are very similar.
In particular, it is found that previously published differences between
measured values of near arise mainly from
different choices of masks in regions of largest Galactic emissions, and that
demonstrated measurement biases are reduced by eliminating masks altogether.
Maps from both satellites are shown to agree with to within
estimated statistical and systematic errors, consistent with an exact symmetry
predicted in a new holographic quantum model of inflation.Comment: resubmitted to ApJ Letters, with revisions in response to referee
comment
Forkhead box transcription factor regulation and lipid accumulation by hepatitis C virus
We have previously shown that hepatitis C virus (HCV) infection modulates the expression of forkhead box transcription factors, including FoxO1 and FoxA2, which play key roles in gluconeogenesis and β-oxidation of fatty acid, respectively. The aim of the present study was to determine the role of forkhead box transcription factors in modulating lipid metabolism. HCV infection or core protein expression alone in transfected Huh7.5 cells increased expression of sterol regulatory element binding protein 1c (SREBP-1c) and its downstream target, fatty acid synthase (FASN), which are key proteins involved in lipid synthesis. Knockdown of FoxO1 by small interfering RNA in HCV-infected cells significantly decreased SREBP-1c and FASN expression. Further, HCV infection or core protein expression in Huh7.5 cells significantly decreased the expression of medium-chain acyl coenzyme A dehydrogenase (MCAD) and short-chain acyl coenzyme A dehydrogenase (SCAD), involved in the regulation of β-oxidation of fatty acids. Ectopic expression of FoxA2 in HCV-infected cells rescued the expression of MCAD and SCAD. Oil red O and neutral lipid staining indicated that HCV infection significantly increases lipid accumulation compared to that in the mock-infected control. This was further verified by the increased expression of perilipin-2 and decreased activity of hormone-sensitive lipase (HSL) in HCV-infected hepatocytes, implying increased accumulation of neutral lipids. Knockdown of FoxO1 and ectopic expression of FoxA2 significantly decreased HCV replication. Taken together, these results suggest that HCV modulates forkhead box transcription factors which together increase lipid accumulation and promote viral replication. IMPORTANCE Hepatic steatosis is a frequent complication associated with chronic HCV infection. Its presence is a key prognostic indicator associated with the progression to hepatic fibrosis and hepatocellular carcinoma. Several mechanisms have been proposed to account for the development of steatosis and fatty liver during HCV infection. We observed that HCV infection increases expression of both SREBP-1c and FASN. Further investigation suggested that the expression of SREBP-1c and FASN is controlled by the transcription factor FoxO1 during HCV infection. In addition, HCV infection significantly decreased both MCAD and SCAD expression, which is controlled by FoxA2. HCV infection also increased lipid droplet accumulation, increased perilipin-2 expression, and decreased HSL activity. Thus, knockdown of FoxO1 (decreased lipogenesis) and overexpression of FoxA2 (increased β-oxidation) resulted in a significant disruption of the platform and, hence, a decrease in HCV genome replication. Thus, targeting of FoxO1 and FoxA2 might be useful in developing a therapeutic approach against HCV infection
Interferometric Constraints on Quantum Geometrical Shear Noise Correlations
Final measurements and analysis are reported from the first-generation
Holometer, the first instrument capable of measuring correlated variations in
space-time position at strain noise power spectral densities smaller than a
Planck time. The apparatus consists of two co-located, but independent and
isolated, 40 m power-recycled Michelson interferometers, whose outputs are
cross-correlated to 25 MHz. The data are sensitive to correlations of
differential position across the apparatus over a broad band of frequencies up
to and exceeding the inverse light crossing time, 7.6 MHz. By measuring with
Planck precision the correlation of position variations at spacelike
separations, the Holometer searches for faint, irreducible correlated position
noise backgrounds predicted by some models of quantum space-time geometry. The
first-generation optical layout is sensitive to quantum geometrical noise
correlations with shear symmetry---those that can be interpreted as a
fundamental noncommutativity of space-time position in orthogonal directions.
General experimental constraints are placed on parameters of a set of models of
spatial shear noise correlations, with a sensitivity that exceeds the
Planck-scale holographic information bound on position states by a large
factor. This result significantly extends the upper limits placed on models of
directional noncommutativity by currently operating gravitational wave
observatories.Comment: Matches the journal accepted versio
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