3 research outputs found
The influence of food texture and liquid consistency modification on swallowing physiology and function: a systematic review
Texture modification has become one of the most common forms of intervention for dysphagia, and is widely considered important for promoting safe and efficient swallowing. However, to date, there is no single convention with respect to the terminology used to describe levels of liquid thickening or food texture modification for clinical use. As a first step towards building a common taxonomy, a systematic review was undertaken to identify empirical evidence describing the impact of liquid consistency and food texture on swallowing behavior. A multi-engine search yielded 10,147 non-duplicate articles, which were screened for relevance. A team of 10 international researchers collaborated to conduct full-text reviews for 488 of these articles, which met the study inclusion criteria. Of these, 36 articles were found to contain information comparing oral processing or swallowing behaviors for at least two liquid consistencies or food textures. Qualitative synthesis revealed two key trends with respect to the impact of thickening liquids on swallowing: thicker liquids reduce the risk of penetration-aspiration, but also increase the risk of post-swallow residue in the pharynx. The literature was insufficient to support the delineation of specific viscosity boundaries or other quantifiable material properties related to these clinical outcomes. With respect to food texture, the literature pointed to properties of hardness, cohesiveness and slipperiness as relevant both for physiological behaviors and bolus flow patterns. The literature suggests a need to classify food and fluid behavior in the context of the physiological processes involved in oral transport and flow initiation
Theta dependence of SU(N) gauge theories in the presence of a topological term
We review results concerning the theta dependence of 4D SU(N) gauge theories
and QCD, where theta is the coefficient of the CP-violating topological term in
the Lagrangian. In particular, we discuss theta dependence in the large-N
limit.
Most results have been obtained within the lattice formulation of the theory
via numerical simulations, which allow to investigate the theta dependence of
the ground-state energy and the spectrum around theta=0 by determining the
moments of the topological charge distribution, and their correlations with
other observables. We discuss the various methods which have been employed to
determine the topological susceptibility, and higher-order terms of the theta
expansion. We review results at zero and finite temperature. We show that the
results support the scenario obtained by general large-N scaling arguments, and
in particular the Witten-Veneziano mechanism to explain the U(1)_A problem. We
also compare with results obtained by other approaches, especially in the
large-N limit, where the issue has been also addressed using, for example, the
AdS/CFT correspondence.
We discuss issues related to theta dependence in full QCD: the neutron
electric dipole moment, the dependence of the topological susceptibility on the
quark masses, the U(1)_A symmetry breaking at finite temperature.
We also consider the 2D CP(N) model, which is an interesting theoretical
laboratory to study issues related to topology. We review analytical results in
the large-N limit, and numerical results within its lattice formulation.
Finally, we discuss the main features of the two-point correlation function
of the topological charge density.Comment: A typo in Eq. (3.9) has been corrected. An additional subsection
(5.2) has been inserted to demonstrate the nonrenormalizability of the
relevant theta parameter in the presence of massive fermions, which implies
that the continuum (a -> 0) limit must be taken keeping theta fixe