The Experts below are selected from a list of 2949 Experts worldwide ranked by ideXlab platform
Kita Nanao - One of the best experts on this subject based on the ideXlab platform.
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Bipartite Graft II: Cathedral Decomposition for Combs
2021Co-Authors: Kita NanaoAbstract:We provide a canonical decomposition for a class of bipartite grafts known as combs. As every bipartite graft is a recursive combination of combs, our results provides a canonical decomposition for general bipartite grafts. Our new decomposition is by definition a generalization of the classical canonical decomposition in matching theory, that is, the Dulmage-Mendelsohn decomposition for bipartite graphs with perfect matchings. However, it exhibits much more complicated structure than its classical counterpart. It is revealed from our results that bipartite grafts has a canonical structure that is analogous to the cathedral decomposition for nonbipartite graphs with perfect matchings
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Bipartite Graft I: Dulmage-Mendelsohn Decomposition for Combs
2020Co-Authors: Kita NanaoAbstract:We provide an analogue of the Dulmage-Mendelsohn decomposition for a class of grafts known as comb-bipartite grafts. The Dulmage-Mendelsohn decomposition in matching theory is a classical canonical structure theorem for bipartite graphs. The substantial part of this classical theorem resides in bipartite graphs that are factorizable, that is, those with a perfect matching. Minimum joins in grafts, also known as minimum $T$-joins in graphs, is a generalization of perfect matchings in factorizable graphs. Seb\"o revealed in his paper that comb-bipartite grafts form one of the two fundamental classes of grafts that serve as skeletons or building blocks of any grafts. Particularly, any bipartite grafts, that is, bipartite counterpart of grafts, can be considered as a recursive combination of comb-bipartite grafts. In this paper, we generalize the Dulmage-Mendelsohn decomposition for comb-bipartite grafts. We also show for this decomposition a property that is characteristics to grafts using the general Kotzig-Lov\'asz decomposition for grafts, which is a known graft analogue of another canonical structure theorem from matching theory. This paper is the first from a series of studies regarding bipartite grafts
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Nonbipartite Dulmage-Mendelsohn Decomposition for Berge Duality
2017Co-Authors: Kita NanaoAbstract:The Dulmage-Mendelsohn decomposition is a classical canonical decomposition in matching theory applicable for bipartite graphs, and is famous not only for its application in the field of matrix computation, but also for providing a prototypal structure in matroidal optimization theory. The Dulmage-Mendelsohn decomposition is stated and proved using the two color classes, and therefore generalizing this decomposition for nonbipartite graphs has been a difficult task. In this paper, we obtain a new canonical decomposition that is a generalization of the Dulmage-Mendelsohn decomposition for arbitrary graphs, using a recently introduced tool in matching theory, the basilica decomposition. Our result enables us to understand all known canonical decompositions in a unified way. Furthermore, we apply our result to derive a new theorem regarding barriers. The duality theorem for the maximum matching problem is the celebrated Berge formula, in which dual optimizers are known as barriers. Several results regarding maximal barriers have been derived by known canonical decompositions, however no characterization has been known for general graphs. In this paper, we provide a characterization of the family of maximal barriers in general graphs, in which the known results are developed and unified
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The Dulmage-Mendelsohn Decomposition for $b$-Matchings
2016Co-Authors: Kita NanaoAbstract:We establish the theory of the Dulmage-Mendelsohn decomposition for $b$-matchings. The original Dulmage-Mendelsohn decomposition is a classical canonical decomposition of bipartite graphs, which describes the structures of the maximum $1$-matchings and the dual optimizers, i.e., the minimum vertex covers. In this paper, we develop analogical properties, and thus obtain the structure of the maximum $b$-matchings and characterizes the family of $b$-verifying set
Taher Omari - One of the best experts on this subject based on the ideXlab platform.
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biomechanical quantification of Mendelsohn maneuver and effortful swallowing on pharyngoesophageal function
Otolaryngology-Head and Neck Surgery, 2017Co-Authors: Sebastian H Doeltgen, Ellisa Ong, Ingrid Scholten, Charles Cock, Taher OmariAbstract:Objective To quantify the effects of 2 swallowing maneuvers used in dysphagia rehabilitation-the Mendelsohn maneuver and effortful swallowing-on pharyngoesophageal function with novel, objective pressure-flow analysis. Study Design Evaluation of intervention effects in a healthy control cohort. Setting A pharyngoesophageal motility research laboratory in a tertiary education facility. Subjects Twelve young healthy subjects (9 women, 28.6 ± 7.9 years) from the general public, without swallowing impairment, volunteered to participate in this study. Methods Surface electromyography from the floor-of-mouth musculature and high-resolution impedance manometry-based pressure flow analysis were used to assess floor-of-mouth activation and pharyngoesophageal motility, respectively. Subjects each performed 10 noneffortful control swallows, Mendelsohn maneuver swallows, and effortful swallows, with a 5-mL viscous bolus. Repeated measures analyses of variance was used to compare outcome measures across conditions. Results Effortful and Mendelsohn swallows generated greater floor-of-mouth contraction ( P = .001) and pharyngeal pressure ( P < .0001) when compared with control swallows. There were no changes at the level of the upper esophageal sphincter, except for a faster opening to maximal diameter during maneuver swallows ( P = .01). The proximal esophageal contractile integral was reduced during Mendelsohn swallows ( P = .001). Conclusion Effortful and Mendelsohn maneuver swallows significantly alter the pharyngoesophageal pressure profile. Faster opening of the upper esophageal sphincter may facilitate bolus transfer during maneuver swallows; however, reduced proximal esophageal contractility during Mendelsohn maneuver swallows may impair bolus flow and aggravate dysphagic symptoms.
Damle K. - One of the best experts on this subject based on the ideXlab platform.
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Dulmage-Mendelsohn percolation: Geometry of maximally-packed dimer models and topologically-protected zero modes on diluted bipartite lattices
2021Co-Authors: Bhola R., Biswas S., Islam, Md M., Damle K.Abstract:The classic combinatorial construct of {\em maximum matchings} probes the random geometry of regions with local sublattice imbalance in a site-diluted bipartite lattice. We demonstrate that these regions, which host the monomers of any maximum matching of the lattice, control the localization properties of a zero-energy quantum particle hopping on this lattice. The structure theory of Dulmage and Mendelsohn provides us a way of identifying a complete and non-overlapping set of such regions. This motivates our large-scale computational study of the Dulmage-Mendelsohn decomposition of site-diluted bipartite lattices in two and three dimensions. Our computations uncover an interesting universality class of percolation associated with the end-to-end connectivity of such monomer-carrying regions with local sublattice imbalance, which we dub {\em Dulmage-Mendelsohn percolation}. Our results imply the existence of a monomer percolation transition in the classical statistical mechanics of the associated maximally-packed dimer model and the existence of a phase with area-law entanglement entropy of arbitrary many-body eigenstates of the corresponding quantum dimer model. They also have striking implications for the nature of collective zero-energy Majorana fermion excitations of bipartite networks of Majorana modes localized on sites of diluted lattices, for the character of topologically-protected zero-energy wavefunctions of the bipartite random hopping problem on such lattices, and thence for the corresponding quantum percolation problem, and for the nature of low-energy magnetic excitations in bipartite quantum antiferromagnets diluted by a small density of nonmagnetic impurities.Comment: minor typos and errors fixed; further clarifications added. no substantive changes in result
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Dulmage-Mendelsohn percolation: Geometry of maximally-packed dimer models and topologically-protected zero modes on diluted bipartite lattices
2021Co-Authors: Bhola R., Biswas S., Islam, Md M., Damle K.Abstract:We study the random geometry of maximum matchings of diluted bipartite lattices such as the diluted square, honeycomb and cubic lattices in two and three dimensions. Our study brings into play a graph-theoretical tool, the {\em Dulmage-Mendelsohn decomposition} of a bipartite graph. Using this, we define two broad classes of non-overlapping connected clusters, ${\mathcal R}$-type and ${\mathcal P}$-type regions, that together cover the diluted lattice. We demonstrate that the size of these regions controls monomer and dimer correlations in the statistical mechanics of the corresponding maximally-packed dimer models. Additionally, we argue that ${\mathcal R}$-type regions host topologically-protected zero modes in the quantum mechanics of a particle hopping on such random lattices. These ${\mathcal R}$-type regions also host emergent Majorana fermion excitations of the corresponding bipartite Majorana networks. In two dimensions, we show that the random geometry of ${\mathcal R}$-type regions exhibits universal scaling behaviour controlled by a diverging localization length in the limit of vanishing dilution $n_{\rm vac} \to 0$. In three dimensions, we demonstrate that these ${\mathcal R}$-type regions display critical scaling behaviour in the vicinity of a "Dulmage-Mendelsohn percolation" transition at a nonzero dilution threshold $n_{\rm vac}^{\rm crit}$ that lies well within the geometrically percolated phase of the diluted cubic lattice. We provide an accurate numerical estimate of $n_{\rm vac}^{\rm crit} $ for the cubic lattice, as well as estimates for the critical exponents and scaling functions that characterise this new universality class of geometric criticality in two and three dimensions.Comment: revised to include additional results on Dulmage-Mendelsohn percolation in three dimension
Kazuhisa Domen - One of the best experts on this subject based on the ideXlab platform.
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effect of the effortful swallow and the Mendelsohn maneuver on tongue pressure production against the hard palate
Dysphagia, 2013Co-Authors: Tatsuyuki Fukuoka, Kazuhiro Hori, Takahiro Ono, Kenichi Tamine, Sonoko Nozaki, Kenji Shimada, Noriyasu Yamamoto, Yoshihiro Fukuda, Kazuhisa DomenAbstract:Although effortful swallow and the Mendelsohn maneuver are commonly used in dysphagia rehabilitation, little is known about their effects on tongue-palate pressure production. The purpose of this study was to investigate the effects of effortful swallow and the Mendelsohn maneuver on tongue pressure production. Fourteen healthy volunteers (10 men, 4 women; age range = 21–41 years) participated. Tongue pressures during dry swallow, water swallow, effortful swallow, and the Mendelsohn maneuver were measured using a sensor sheet system with five measurement points on the hard palate. Sequential order, duration, maximal magnitude, and the integrated value of tongue pressure at each measurement point were compared among the four tasks. Onset of tongue pressure at the posterior-circumferential parts occurred first in the Mendelsohn maneuver; that at the anterior-median part was earlier than at other parts in the effortful swallow. At all measurement points, tongue pressure duration was significantly longer in the Mendelsohn maneuver than in other tasks. Effortful swallow was most effective in increasing tongue pressure. The integrated value of tongue pressure at the posterior-circumferential parts in the Mendelsohn maneuver and at the median parts in the effortful swallow showed a tendency to increase. These results suggest that tongue pressure increases along a wide part of the hard palate in effortful swallow because the anchor of tongue movement is emphasized at the anterior part of the hard palate. The Mendelsohn maneuver provides prolonged and accentuated tongue-palate contact at the posterior-circumferential parts, which might be important for hyoid-laryngeal elevation during swallowing.
Timothy M Mcculloch - One of the best experts on this subject based on the ideXlab platform.
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High-Resolution Manometry of Pharyngeal Swallow Pressure Events Associated with Effortful Swallow and the Mendelsohn Maneuver
Dysphagia, 2012Co-Authors: Matthew R Hoffman, Jason D Mielens, Michelle R Ciucci, Jack J Jiang, Corinne A Jones, Timothy M MccullochAbstract:Effortful swallow and the Mendelsohn maneuver are two common strategies to improve disordered swallowing. We used high-resolution manometry (HRM) to quantify the effects of these maneuvers on pressure and timing characteristics. Fourteen normal subjects swallowed multiple, 5-ml water boluses using three techniques: normal swallow, effortful swallow, and the Mendelsohn maneuver. Maximum pressure, rate, duration, area integral, and line integral were determined for the velopharynx and tongue base. Minimum pressure, duration of pressure-related change, duration of nadir pressure, maximum preopening and postclosure pressure, area integral, and line integral were recorded for the upper esophageal sphincter (UES). Area and line integrals of the velopharyngeal pressure curve significantly increased with the Mendelsohn maneuver; the line integral increased with the effortful swallow. Preopening UES pressure decreased significantly for the Mendelsohn, while postclosure pressure tended to increase insignificantly for both maneuvers. UES area and line integrals as well as nadir UES pressure duration increased with both maneuvers. Maneuver-dependent changes were observed primarily at the velopharynx and UES. These regions are critical to safe swallowing, as the velopharynx provides positive pressure at the bolus tail while the UES allows a bolus to enter the esophagus without risk of regurgitation. Integrals were more responsive than maximum pressure or duration and should be investigated further.