56,468 research outputs found
Modality effects in vocabulary acquisition
It is unknown whether modality affects the efficiency with which humans learn novel word forms and their meanings, with previous studies reporting both written and auditory advantages. The current study implements controls whose absence in previous work likely offers explanation for such contradictory findings. In two novel word learning experiments, participants were trained and tested on pseudoword - novel object pairs, with controls on: modality of test, modality of meaning, duration of exposure and transparency of word form. In both experiments word forms were presented in either their written or spoken form, each paired with a pictorial meaning (novel object). Following a 20-minute filler task, participants were tested on their ability to identify the picture-word form pairs on which they were trained. A between subjects design generated four participant groups per experiment 1) written training, written test; 2) written training, spoken test; 3) spoken training, written test; 4) spoken training, spoken test. In Experiment 1 the written stimulus was presented for a time period equal to the duration of the spoken form. Results showed that when the duration of exposure was equal, participants displayed a written training benefit. Given words can be read faster than the time taken for the spoken form to unfold, in Experiment 2 the written form was presented for 300 ms, sufficient time to read the word yet 65% shorter than the duration of the spoken form. No modality effect was observed under these conditions, when exposure to the word form was equivalent. These results demonstrate, at least for proficient readers, that when exposure to the word form is controlled across modalities the efficiency with which word form-meaning associations are learnt does not differ. Our results therefore suggest that, although we typically begin as aural-only word learners, we ultimately converge on developing learning mechanisms that learn equally efficiently from both written and spoken materials
A system to geometrically rectify and map airborne scanner imagery and to estimate ground area
A system of computer programs were developed which performs geometric rectification and line-by-line mapping of airborne multispectral scanner data to ground coordinates and estimates ground area. The system requires aircraft attitude and positional information furnished by ancillary aircraft equipment, as well as ground control points. The geometric correction and mapping procedure locates the scan lines, or the pixels on each line, in terms of map grid coordinates. The area estimation procedure gives ground area for each pixel or for a predesignated parcel specified in map grid coordinates. The results of exercising the system with simulated data showed the uncorrected video and corrected imagery and produced area estimates accurate to better than 99.7%
The role of memory and restricted context in repeated visual search
Previous studies have shown that the efficiency of visual search does not improve when participants search
through the same unchanging display for hundreds of trials (repeated search), even though the participants have
a clear memory of the search display. In this article, we ask two important questions. First, why do participants
not use memory to help search the repeated display? Second, can context be introduced so that participants are
able to guide their attention to the relevant repeated items? Experiments 1–4 show that participants choose not
to use a memory strategy because, under these conditions, repeated memory search is actually less efficient than
repeated visual search, even though the latter task is in itself relatively inefficient. However, when the visual
search task is given context, so that only a subset of the items are ever pertinent, participants can learn to restrict
their attention to the relevant stimuli (Experiments 5 and 6)
Relaxation dynamics of a protein solution investigated by dielectric spectroscopy
In the present work, we provide a dielectric study on two differently
concentrated aqueous lysozyme solutions in the frequency range from 1 MHz to 40
GHz and for temperatures from 275 to 330 K. We analyze the three dispersion
regions, commonly found in protein solutions, usually termed beta-, gamma-, and
delta-relaxation. The beta-relaxation, occurring in the frequency range around
10 MHz and the gamma-relaxation around 20 GHz (at room temperature) can be
attributed to the rotation of the polar protein molecules in their aqueous
medium and the reorientational motion of the free water molecules,
respectively. The nature of the delta-relaxation, which often is ascribed to
the motion of bound water molecules, is not yet fully understood. Here we
provide data on the temperature dependence of the relaxation times and
relaxation strengths of all three detected processes and on the dc conductivity
arising from ionic charge transport. The temperature dependences of the beta-
and gamma-relaxations are closely correlated. We found a significant
temperature dependence of the dipole moment of the protein, indicating
conformational changes. Moreover we find a breakdown of the
Debye-Stokes-Einstein relation in this protein solution, i.e., the dc
conductivity is not completely governed by the mobility of the solvent
molecules. Instead it seems that the dc conductivity is closely connected to
the hydration shell dynamics.Comment: 11 pages, 7 figure
Subsampling inference in cube root asymptotics with an application to Manski's maximum score estimator
Kim and Pollard (Annals of Statistics, 18 (1990) 191?219) showed that a general class of M-estimators converge at rate n1/3 rather than at the standard rate n1/2. Many times, this situation arises when the objective function is non-smooth. The limiting distribution is the (almost surely unique) random vector that maximizes a certain Gaussian process and is difficult to analyze analytically. In this paper, we propose the use of the subsampling method for inferential purposes. The general method is then applied to Manski?s maximum score estimator and its small sample performance is highlighted via a simulation study.Publicad
A tour on Hermitian symmetric manifolds
Hermitian symmetric manifolds are Hermitian manifolds which are homogeneous
and such that every point has a symmetry preserving the Hermitian structure.
The aim of these notes is to present an introduction to this important class of
manifolds, trying to survey the several different perspectives from which
Hermitian symmetric manifolds can be studied.Comment: 56 pages, expanded version. Written for the Proceedings of the
CIME-CIRM summer course "Combinatorial Algebraic Geometry". Comments are
still welcome
Non-Locality of Experimental Qutrit Pairs
The insight due to John Bell that the joint behavior of individually measured
entangled quantum systems cannot be explained by shared information remains a
mystery to this day. We describe an experiment, and its analysis, displaying
non-locality of entangled qutrit pairs. The non-locality of such systems, as
compared to qubit pairs, is of particular interest since it potentially opens
the door for tests of bipartite non-local behavior independent of probabilistic
Bell inequalities, but of deterministic nature
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