24,439 research outputs found
The development of a tape recording for appreciative listening to choral speaking in the fourth grade
Thesis (Ed.M.)--Boston Universit
Egocentric Reference Frame Bias In The Palmar Haptic Perception Of Surface Orientation
The effect of egocentric reference frames on palmar haptic perception of orientation was investigated in vertically separated locations in a sagittal plane. Reference stimuli to be haptically matched were presented either haptically (to the contralateral hand) or visually. As in prior investigations of haptic orientation perception, a strong egocentric bias was found, such that haptic orientation matches made in the lower part of personal space were much lower (i.e., were perceived as being higher) than those made at eye level. The same haptic bias was observed both when the reference surface to be matched was observed visually and when bimanual matching was used. These findings support the conclusion that, despite the presence of an unambiguous allocentric (gravitational) reference frame in vertical planes, haptic orientation perception in the sagittal plane reflects an egocentric bias
Genus two mutant knots with the same dimension in knot Floer and Khovanov homologies
We exhibit an infinite family of knots with isomorphic knot Heegaard Floer
homology. Each knot in this infinite family admits a nontrivial genus two
mutant which shares the same total dimension in both knot Floer homology and
Khovanov homology. Each knot is distinguished from its genus two mutant by both
knot Floer homology and Khovanov homology as bigraded groups. Additionally, for
both knot Heegaard Floer homology and Khovanov homology, the genus two mutation
interchanges the groups in -gradings and .Comment: Information about -graded homology has been changed along
with statement of Theorem 1 and Table 1. Significant changes to Section
Surgery on links of linking number zero and the Heegaard Floer -invariant
We study Heegaard Floer homology and various related invariants (such as the
-function) for two-component L-space links with linking number zero. For
such links, we explicitly describe the relationship between the -function,
the Sato-Levine invariant and the Casson invariant. We give a formula for the
Heegaard Floer -invariants of integral surgeries on two-component L-space
links of linking number zero in terms of the -function, generalizing a
formula of Ni and Wu. As a consequence, for such links with unknotted
components, we characterize L-space surgery slopes in terms of the
-invariants of the knots obtained from blowing down the components.
We give a proof of a skein inequality for the -invariants of
surgeries along linking number zero links that differ by a crossing change. We
also describe bounds on the smooth four-genus of links in terms of the
-function, expanding on previous work of the second author, and use these
bounds to calculate the four-genus in several examples of links.Comment: This version accepted for publication in Quantum Topolog
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