2,923 research outputs found
Thin films with high surface roughness: thickness and dielectric function analysis using spectroscopic ellipsometry
An optical surface roughness model is presented, which allows a reliable determination of the dielectric function of thin films with high surface roughnesses of more than 10 nm peak to valley distance by means of spectroscopic ellipsometry. Starting from histogram evaluation of atomic force microscopy (AFM) topography measurements a specific roughness layer (RL) model was developed for an organic thin film grown in vacuum which is well suited as an example. Theoretical description based on counting statistics allows generalizing the RL model developed to be used for all non-conducting materials. Finally, a direct input of root mean square (RMS) values found by AFM measurements into the proposed model is presented, which is important for complex ellipsometric evaluation models where a reduction of the amount of unknown parameters can be crucial. Exemplarily, the evaluation of a N,Nâ-dimethoxyethyl-3,4,9,10-perylene-tetracarboxylic-diimide (DiMethoxyethyl-PTCDI) film is presented, which exhibits a very high surface roughness, i.e. showing no homogeneous film at all
The resting microstate networks (RMN): cortical distributions, dynamics, and frequency specific information flow
A brain microstate is characterized by a unique, fixed spatial distribution
of electrically active neurons with time varying amplitude. It is hypothesized
that a microstate implements a functional/physiological state of the brain
during which specific neural computations are performed. Based on this
hypothesis, brain electrical activity is modeled as a time sequence of
non-overlapping microstates with variable, finite durations (Lehmann and
Skrandies 1980, 1984; Lehmann et al 1987). In this study, EEG recordings from
109 participants during eyes closed resting condition are modeled with four
microstates. In a first part, a new confirmatory statistics method is
introduced for the determination of the cortical distributions of electric
neuronal activity that generate each microstate. All microstates have common
posterior cingulate generators, while three microstates additionally include
activity in the left occipital/parietal, right occipital/parietal, and anterior
cingulate cortices. This appears to be a fragmented version of the
metabolically (PET/fMRI) computed default mode network (DMN), supporting the
notion that these four regions activate sequentially at high time resolution,
and that slow metabolic imaging corresponds to a low-pass filtered version. In
the second part of this study, the microstate amplitude time series are used as
the basis for estimating the strength, directionality, and spectral
characteristics (i.e., which oscillations are preferentially transmitted) of
the connections that are mediated by the microstate transitions. The results
show that the posterior cingulate is an important hub, sending alpha and beta
oscillatory information to all other microstate generator regions.
Interestingly, beyond alpha, beta oscillations are essential in the maintenance
of the brain during resting state.Comment: pre-print, technical report, The KEY Institute for Brain-Mind
Research (Zurich), Kansai Medical University (Osaka
EEG Microstates During Resting Represent Personality Differences
We investigated the spontaneous brain electric activity of 13 skeptics and 16 believers in paranormal phenomena; they were university students assessed with a self-report scale about paranormal beliefs. 33-channel EEG recordings during no-task resting were processed as sequences of momentary potential distribution maps. Based on the maps at peak times of Global Field Power, the sequences were parsed into segments of quasi-stable potential distribution, the âmicrostates'. The microstates were clustered into four classes of map topographies (A-D). Analysis of the microstate parameters time coverage, occurrence frequency and duration as well as the temporal sequence (syntax) of the microstate classes revealed significant differences: Believers had a higher coverage and occurrence of class B, tended to decreased coverage and occurrence of class C, and showed a predominant sequence of microstate concatenations from A to C to B to A that was reversed in skeptics (A to B to C to A). Microstates of different topographies, putative "atoms of thoughtâ, are hypothesized to represent different types of information processing.The study demonstrates that personality differences can be detected in resting EEG microstate parameters and microstate syntax. Microstate analysis yielded no conclusive evidence for the hypothesized relation between paranormal belief and schizophreni
Make your brand heard: A qualitative study on the use of corporate podcasts as a branding tool
As an increasingly popular on-demand medium, podcasts have become more professional and commercialized in recent times. This is also evident from a look at corporate communications, where many companies add podcasts into their communication mix. To align these corporate podcasts with other communication channels, the concept of corporate branding can be helpful. This approach has not been considered by empirical studies so far. Our qualitative interview study wants to investigate the role of corporate podcasts in corporate branding and examines their integration into the communication strategy of nationally and internationally operating companies. 13 experts from large companies responsible for the respective podcast have been interviewed. The research results show that podcasts are mostly integrated into the companyâs overarching communications strategy and incorporate company-specific branding aspects to varying degrees. Corporate podcasts are primarily used to highlight innovative and modern aspects of the brands, especially through the tone of voice. The intended impact of corporate podcasts is often a personal and emotional connection, interaction, and resonance with listeners. Increasing reputation, visibility, and conveying authenticity is also targeted. As a branding tool, podcasts are evaluated rather implicitly. The general evaluation is perceived as challenging and tends to focus on qualitative performance measurement. This study underscores the high need for research on corporate podcasts as a branding tool as well as for key performance indicators (KPIs) of podcasts
First Valence, Then Arousal: The Temporal Dynamics of Brain Electric Activity Evoked by Emotional Stimuli
The temporal dynamics of the neural activity that implements the dimensions valence and arousal during processing of emotional stimuli were studied in two multi-channel ERP experiments that used visually presented emotional words (experiment1) and emotional pictures (experiment2) as stimulus material. Thirty-two healthy subjects participated (mean age 26.8±6.4years, 24 women). The stimuli in both experiments were selected on the basis of verbal reports in such a way that we were able to map the temporal dynamics of one dimension while controlling for the other one. Words (pictures) were centrally presented for 450 (600) ms with interstimulus intervals of 1,550 (1,400) ms. ERP microstate analysis of the entire epochs of stimulus presentations parsed the data into sequential steps of information processing. The results revealed that in several microstates of both experiments, processing of pleasant and unpleasant valence (experiment1, microstate #3: 118-162ms, #6: 218-238ms, #7: 238-266ms, #8: 266-294ms; experiment2, microstate #5: 142-178ms, #6: 178-226ms, #7: 226-246ms, #9: 262-302ms, #10: 302-330ms) as well as of low and high arousal (experiment1, microstate #8: 266-294ms, #9: 294-346ms; experiment2, microstate #10: 302-330ms, #15: 562-600ms) involved different neural assemblies. The results revealed also that in both experiments, information about valence was extracted before information about arousal. The last microstate of valence extraction was identical with the first microstate of arousal extractio
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