16,417 research outputs found
Meanings of fractions as demonstrated by future primary teachers in the initial phase of teacher education
Fractions are a fundamental content of primary-level education and must therefore be included in the training courses for primary school teachers. Experts argue that deep understanding is required to improve primary school teachers’ knowledge of this mathematical concept (Ball, 1990; Cramer, Post & del Mas, 2002; Newton, 2008). Our study focuses on the part-whole relationship as a crucial foundation in working with fractions. This paper characterizes some of the meanings of this relationship for a group of future primary school teachers
Meaning of the part-whole relation and the concept of fraction for primary teachers
The part-whole relation is complex and raises questions that affect different disciplines. Researchers have proposed different interpretations of the notions of fraction and rational number (e.g., Behr, Lesh, Post & Silver, 1983; Kieren, 1976). We highlight three kinds of relations in the study of rational numbers—the part whole-relation, the part-part relation, and the functional relation—through which we organize the different subconstructs of rational number. We claim that the meaning of fractions should be understood through three components: their mathematical structure, their representations and their senses
Dirac points merging and wandering in a model Chern insulator
We present a model for a Chern insulator on the square lattice with complex
first and second neighbor hoppings and a sublattice potential which displays an
unexpectedly rich physics. Similarly to the celebrated Haldane model, the
proposed Chern insulator has two topologically non-trivial phases with Chern
numbers . As a distinctive feature of the present model, phase
transitions are associated to Dirac points that can move, merge and split in
momentum space, at odds with Haldane's Chern insulator where Dirac points are
bound to the corners of the hexagonal Brillouin zone. Additionally, the
obtained phase diagram reveals a peculiar phase transition line between two
distinct topological phases, in contrast to the Haldane model where such
transition is reduced to a point with zero sublattice potential. The model is
amenable to be simulated in optical lattices, facilitating the study of phase
transitions between two distinct topological phases and the experimental
analysis of Dirac points merging and wandering
Mirror therapy and self-care autonomy after stroke: an intervention program
Background: In patients with middle cerebral artery (MCA) stroke, changes in upper limb function lead to dependence
on others for self-care. In the process of recovering autonomy/independence, there is evidence on the
effectiveness of sensory stimulation techniques in the motor recovery after stroke.
Objective: To assess the effect of mirror therapy on the self-care autonomy of patients with hemiplegia/hemiparesis
due to MCA stroke.
Methodology: Cross-sectional and quasi-experimental study with a quantitative approach, a before-and-after design,
and a non-equivalent control group. A nonprobability sample of 30 participants was selected.
Results: Gains in grip strength, joint range of motion, and manual dexterity of the upper limb were more significant
in the experimental group but without statistically significant differences between groups.
Conclusion: Despite the more significant evolution of the experimental group, mirror therapy was not effective
in the motor recovery of the upper limb. Further studies are needed in this area using randomized designs, larger
samples, and focused on self-care
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