Topological characterization of rearrangements in amorphous solids.

In amorphous materials, plasticity is localized and occurs as shear transformations. It was recently shown by Wu et al. that these shear transformations can be predicted by applying topological defect concepts developed for liquid crystals to an analysis of vibrational eigenmodes [Z. W. Wu et al., Nat. Commun. 14, 2955 (2023)10.1038/s41467-023-38547-w]. This study relates the -1 topological defects to the displacement fields expected of an Eshelby inclusion, which are characterized by an orientation and the magnitude of the eigenstrain. A corresponding orientation and magnitude can be defined for each defect using the local displacement field around each defect. These parameters characterize the plastic stress relaxation associated with the local structural rearrangement and can be extracted using the fit to either the global displacement field or the local field. Both methods provide a reasonable estimation of the molecular-dynamics-measured stress drop, confirming the localized nature of the displacements that control both long-range deformation and stress relaxation.

Thermal effects in the shear-transformation-zone theory of amorphous plasticity: comparisons to metallic glass data.

We extend our earlier shear-transformation-zone theory of amorphous plasticity to include the effects of thermally assisted molecular rearrangements. This version of our theory is a substantial revision and generalization of conventional theories of flow in noncrystalline solids. As in our earlier work, it predicts a dynamic transition between jammed and flowing states at a yield stress. Below that yield stress, it now describes thermally assisted creep. We show that this theory accounts for the experimentally observed strain-rate dependence of the viscosity of metallic glasses, and that it also captures many of the details of the transient stress-strain behavior of those materials during loading. In particular, it explains the apparent onset of superplasticity at sufficiently high stress as a transition between creep at low stresses and plastic flow near the yield stress. We also argue that there are internal inconsistencies in the conventional theories of these deformation processes, and suggest ways in which further experimentation as well as theoretical analysis may lead to better understanding of a broad range of nonequilibrium phenomena.

[The integration of teaching and care in a teaching institution and in a teaching hospital of Porto Alegre: the experience of a working group]. / Integração docente-assistencial entre uma instituição de ensino e um hospital de ensino de Porto Alegre: experiência de um grupo de trabalho.

This study presents the first stage of the work developed by teachers from The School of Nursing of Universidade Federal do Rio Grande do Sul and nurses from Hospital de Clínicas de Porto Alegre in order to elaborate a Project for Teaching-Assistance Integration. The authors explain their experience in a professional group, the methodology used as well the diagnostic of the reality in those Institutions related to teaching, assistance, research and administration.

Social response to acoustic and visual characteristics of oral cleft.

This study was concerned with societal preference among speech, visual, and speech-visual characteristics of persons with repaired cleft lip and palate. A 16 mm motion film with sound was professionally made of 17 male, adult, cleft lip and palate speakers reading the first paragraph from "The Rainbow Passage." A heterogeneous group of 30 adults rated their preference for each of the conditions-auditory, visual and auditory-visual-on a seven-point equal-appearing intervals scale. A four-factor design analysis of variance with repeated measures was performed to determine whether the thirty judges preferred at least one variable of the three variables tested. Results indicated that this heterogenous population had no preference among auditory, visual, or auditory-visual characteristics of adult males with repaired cleft lip and palate. These variables appear to be considered of equal importance by persons who are representative of the lay public.

A subcortical approach to swallow pattern therapy.

The neuromuscular facilitation technique was experimentally used with tongue-thrust patients in order to examine the results of application of this technique to such a population. Four boys and seven girls with a mean age of 116 months were referred by orthodontists in the greater Detroit area to Children's Hospital of Michigan. Each had previously been diagnosed as manifesting tongue thrust. Brushing, icing, and pressure were applied in a home training program for 6 months. Serial dental models were made at 0,3,6 and 12 months, the latter being used to detect regression 6 months after termination of the therapy regimen. Results are presented to support the contention that neuromuscular facilitation is a useful technique in swallow pattern therapy. Ancillary findings are presented which support the contention that mouth breathing and thumb and finger-sucking precede the onset of tongue thrust.