83,724 research outputs found
Efficacy of Electrical Stimulation Intervention in Treating Adults with Dysphagia: A Systematic Review
Purpose: Dysphagia is a term used for a swallowing disorder resulting from problems with the oral cavity, pharynx, esophagus, or gastroesophageal junction. Dysphagia can have significant impacts on an individual’s quality of life and statistics suggest that nearly 15 million adults in the United States present with swallowing disorders. Common medical complications associated with dysphagia are malnutrition, dehydration, aspiration pneumonia, and even death. Traditional dysphagia treatment (TDT) for adults currently consists of diet modification, compensatory strategies involving postural adjustments, and swallowing exercises to strengthen musculature. The objective of this systematic review is to determine whether electrical stimulation (ES) improves swallowing function in adults with dysphagia.
Methodology: Four indexed databases were searched to obtain studies pertaining to the use of ES in dysphagia treatment and its success. Application of inclusionary and exclusionary criteria narrowed the results and relevant studies were selected for this systematic review. Studies were also hand-selected and appraised for validity to ensure minimal bias.
Results: Results of the selected studies revealed varying statistically significant effects of ES as a treatment for adults with dysphagia. However, many studies suggest ES is most effective in producing positive outcomes when coupled with TDT.
Conclusion: The results of the systematic review suggest efficacy of ES is highest when it is used in conjunction with TDT. Studies with statistically significant results reported on only a minor improvement with ES. None of the studies reported negative outcomes related to ES. Additional research is needed to determine overall efficacy of ES as an evidence-based intervention for adults with dysphagia resulting from various etiologies.https://scholarworks.uvm.edu/csdms/1005/thumbnail.jp
Borcherds-Kac-Moody Symmetry of N=4 Dyons
We consider compactifications of heterotic string theory to four dimensions
on CHL orbifolds of the type T^6 /Z_N with 16 supersymmetries. The exact
partition functions of the quarter-BPS dyons in these models are given in terms
of genus-two Siegel modular forms. Only the N=1,2,3 models satisfy a certain
finiteness condition, and in these cases one can identify a Borcherds-Kac-Moody
superalgebra underlying the symmetry structure of the dyon spectrum. We
identify the real roots, and find that the corresponding Cartan matrices
exhaust a known classification. We show that the Siegel modular form satisfies
the Weyl denominator identity of the algebra, which enables the determination
of all root multiplicities. Furthermore, the Weyl group determines the
structure of wall-crossings and the attractor flows of the theory. For N> 4, no
such interpretation appears to be possible.Comment: 44 pages, 1 figur
Distributive Power Control Algorithm for Multicarrier Interference Network over Time-Varying Fading Channels - Tracking Performance Analysis and Optimization
Distributed power control over interference limited network has received an
increasing intensity of interest over the past few years. Distributed solutions
(like the iterative water-filling, gradient projection, etc.) have been
intensively investigated under \emph{quasi-static} channels. However, as such
distributed solutions involve iterative updating and explicit message passing,
it is unrealistic to assume that the wireless channel remains unchanged during
the iterations. Unfortunately, the behavior of those distributed solutions
under \emph{time-varying} channels is in general unknown. In this paper, we
shall investigate the distributed scaled gradient projection algorithm (DSGPA)
in a pairs multicarrier interference network under a finite-state Markov
channel (FSMC) model. We shall analyze the \emph{convergence property} as well
as \emph{tracking performance} of the proposed DSGPA. Our analysis shows that
the proposed DSGPA converges to a limit region rather than a single point under
the FSMC model. We also show that the order of growth of the tracking errors is
given by \mathcal{O}\(1 \big/ \bar{N}\), where is the \emph{average
sojourn time} of the FSMC. Based on the analysis, we shall derive the
\emph{tracking error optimal scaling matrices} via Markov decision process
modeling. We shall show that the tracking error optimal scaling matrices can be
implemented distributively at each transmitter. The numerical results show the
superior performance of the proposed DSGPA over three baseline schemes, such as
the gradient projection algorithm with a constant stepsize.Comment: To Appear on the IEEE Transaction on Signal Processin
An Elliptical Galaxy Luminosity Function and Velocity Dispersion Sample of Relevance for Gravitational Lensing Statistics
We have selected 42 elliptical galaxies from the literature and estimated
their velocity dispersions at the effective radius (\sigma_{\re}) and at 0.54
effective radii (\vff). We find by a dynamical analysis that the normalized
velocity dispersion of the dark halo of an elliptical galaxy \vdm is roughly
\sigma_{\re} multiplied by a constant, which is almost independent of the
core radius or the anisotropy parameter of each galaxy. Our sample analysis
suggests that \vdm^{*} lies in the range 178-198 km s. The power law
relation we find between the luminosity and the dark matter velocity dispersion
measured in this way is (L/L^{*}) = (\vdm/\vdm^{*})^\gamma, where is
between 2-3. These results are of interest for strong gravitational lensing
statistics studies.
In order to determine the value of \vdm^{*}, we calculate \mstar in the
same \bt band in which \vdm^{*} has been estimated. We select 131
elliptical galaxies as a complete sample set with apparent magnitudes \bt
between 9.26 and 12.19. We find that the luminosity function is well fitted to
the Schechter form, with parameters \mstar = -19.66 + 5, , and the normalization constant Mpc, with the Hubble constant
\hnot = 100 km s Mpc. This normalization implies that
morphology type E galaxies make up (10.8 1.2) per cent of all galaxies.Comment: 18 pages latex, with ps figs included. accepted by New Astronomy
(revised to incorporate referees comments
Numerical study of the optical nonlinearity of doped and gapped graphene: From weak to strong field excitation
Numerically solving the semiconductor Bloch equations within a
phenomenological relaxation time approximation, we extract both the linear and
nonlinear optical conductivities of doped graphene and gapped graphene under
excitation by a laser pulse. We discuss in detail the dependence of second
harmonic generation, third harmonic generation, and the Kerr effects on the
doping level, the gap, and the electric field amplitude. The numerical results
for weak electric fields agree with those calculated from available analytic
perturbation formulas. For strong electric fields when saturation effects are
important, all the effective third order nonlinear response coefficients show a
strong field dependence.Comment: 12 pages with 9 figure
Collective Quartics and Dangerous Singlets in Little Higgs
Any extension of the standard model that aims to describe TeV-scale physics
without fine-tuning must have a radiatively-stable Higgs potential. In little
Higgs theories, radiative stability is achieved through so-called collective
symmetry breaking. In this letter, we focus on the necessary conditions for a
little Higgs to have a collective Higgs quartic coupling. In one-Higgs doublet
models, a collective quartic requires an electroweak triplet scalar. In
two-Higgs doublet models, a collective quartic requires a triplet or singlet
scalar. As a corollary of this study, we show that some little Higgs theories
have dangerous singlets, a pathology where collective symmetry breaking does
not suppress quadratically-divergent corrections to the Higgs mass.Comment: 4 pages; v2: clarified the existing literature; v3: version to appear
in JHE
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