3,272 research outputs found
Some integration formulae which simplify the evaluation of certain integrals in common use by engineers
Integration formulas to simplify evaluation of certain commonly used integral
Preliminary analysis of the effects of pressure space correlations on the vibrations of Apollo flight structure
Vibration response of Apollo skin structure to convected boundary layer turbulenc
On the Proper Treatment of the N400 and P600 in Language Comprehension
Event-Related Potentials (ERPs)âstimulus-locked, scalp-recorded voltage fluctuations caused by
post-synaptic neural activityâhave proven invaluable to the study of language comprehension.
Of interest in the ERP signal are systematic, reoccurring voltage fluctuations called components,
which are taken to reflect the neural activity underlying specific computational operations carried
out in given neuroanatomical networks (cf. NÀÀtÀnen and Picton, 1987). For language processing,
the N400 component and the P600 component are of particular salience (see Kutas et al., 2006,
for a review). The typical approach to determining whether a target word in a sentence leads
to differential modulation of these components, relative to a control word, is to look for effects
on mean amplitude in predetermined time-windows on the respective ERP waveforms, e.g.,
350â550 ms for the N400 component and 600â900 ms for the P600 component. The common
mode of operation in psycholinguistics, then, is to tabulate the presence/absence of N400- and/or
P600-effects across studies, and to use this categorical data to inform neurocognitive models
that attribute specific functional roles to the N400 and P600 component (see Kuperberg, 2007;
Bornkessel-Schlesewsky and Schlesewsky, 2008; Brouwer et al., 2012, for reviews).
Here, we assert that this Waveform-based Component Structure (WCS) approach to ERPs
leads to inconsistent data patterns, and hence, misinforms neurocognitive models of the
electrophysiology of language processing. The reason for this is that the WCS approach ignores
the latent component structure underlying ERP waveforms (cf. Luck, 2005), thereby leading to
conclusions about component structure that do not factor in spatiotemporal component overlap of
the N400 and the P600. This becomes particularly problematic when spatiotemporal component
overlap interacts with differential P600 modulations due to task demands (cf. Kolk et al.,
2003). While the problem of spatiotemporal component overlap is generally acknowledged, and
occasionally invoked to account for within-study inconsistencies in the data, its implications are
often overlooked in psycholinguistic theorizing that aims to integrate findings across studies. We
believe WCS-centric theorizing to be the single largest reason for the lack of convergence regarding
the processes underlying the N400 and the P600, thereby seriously hindering the advancement of
neurocognitive theories and models of language processing
An InceptionTime-Inspired Convolutional Neural Network to Detect Cardiac Abnormalities in Reduced-Lead ECG Data
Interaction between Faraday rotation and Cotton-Mouton effects in polarimetry modeling for NSTX
The evolution of electromagnetic wave polarization is modeled for propagation
in the major radial direction in the National Spherical Torus Experiment (NSTX)
with retroreflection from the center stack of the vacuum vessel. This modeling
illustrates that the Cotton-Mouton effect-elliptization due to the magnetic
field perpendicular to the propagation direction-is shown to be strongly
weighted to the high-field region of the plasma. An interaction between the
Faraday rotation and Cotton-Mouton effects is also clearly identified.
Elliptization occurs when the wave polarization direction is neither parallel
nor perpendicular to the local transverse magnetic field. Since Faraday
rotation modifies the polarization direction during propagation, it must also
affect the resultant elliptization. The Cotton-Mouton effect also intrinsically
results in rotation of the polarization direction, but this effect is less
significant in the plasma conditions modeled. The interaction increases at
longer wavelength, and complicates interpretation of polarimetry measurements.Comment: Contributed paper published as part of the Proceedings of the 18th
Topical Conference on High-Temperature Plasma Diagnostics, Wildwood, New
Jersey, May, 201
On the predictability of event boundaries in discourse : An ERP investigation
When reading a text describing an everyday activity, comprehenders build a model of the situation described that includes prior knowledge of the entities, locations, and sequences of actions that typically occur within the event. Previous work has demonstrated that such knowledge guides the processing of incoming information by making event boundaries more or less expected. In the present ERP study, we investigated whether comprehendersâ expectations about event boundaries are influenced by how elaborately common events are described in the context. Participants read short stories in which a common activity (e.g., washing the dishes) was described either in brief or in an elaborate manner. The final sentence contained a target word referring to a more predictable action marking a fine event boundary (e.g., drying) or a less predictable action, marking a coarse event boundary (e.g., jogging). The results revealed a larger N400 effect for coarse event boundaries compared to fine event boundaries, but no interaction with description length. Between 600 and 1000 ms, however, elaborate contexts elicited a larger frontal positivity compared to brief contexts. This effect was largely driven by less predictable targets, marking coarse event boundaries. We interpret the P600 effect as indexing the updating of the situation model at event boundaries, consistent with Event Segmentation Theory (EST). The updating process is more demanding with coarse event boundaries, which presumably require the construction of a new situation model
Splitting event-related potentials: Modeling latent components using regression-based waveform estimation
Eventârelated potentials (ERPs) provide a multidimensional and realâtime window into neurocognitive processing. The typical Waveformâbased Component Structure (WCS) approach to ERPs assesses the modulation pattern of componentsâsystematic, reoccurring voltage fluctuations reflecting specific computational operationsâby looking at mean amplitude in predetermined timeâwindows. This WCS approach, however, often leads to inconsistent results within as well as across studies. It has been argued that at least some inconsistencies may be reconciled by considering spatiotemporal overlap between components; that is, components may overlap in both space and time, and given their additive nature, this means that the WCS may fail to accurately represent its underlying latent component structure (LCS). We employ regressionâbased ERP (rERP) estimation to extend traditional approaches with an additional layer of analysis, which enables the explicit modeling of the LCS underlying WCS. To demonstrate its utility, we incrementally derive an rERP analysis of a recent study on language comprehension with seemingly inconsistent WCSâderived results. Analysis of the resultant regression models allows one to derive an explanation for the WCS in terms of how relevant regression predictors combine in space and time, and crucially, how individual predictors may be mapped onto unique components in LCS, revealing how these spatiotemporally overlap in the WCS. We conclude that rERP estimation allows for investigating how scalpârecorded voltages derive from the spatiotemporal combination of experimentally manipulated factors. Moreover, when factors can be uniquely mapped onto components, rERPs may offer explanations for seemingly inconsistent ERP waveforms at the level of their underlying latent component structure
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