Search results for " function"

Influence of axial mirror ratios on the kinetic instability threshold in electron cyclotron resonance ion source plasma

2022

International audience; Electron Cyclotron Resonance (ECR) ion source plasmas are prone to kinetic instabilities. The onset of the instabilities manifests as emission of microwaves, bursts of electrons expelled from the plasma volume, and the collapse of the extracted highly charged ion (HCI) currents. Consequently, the instabilities limit the HCI performance of ECR ion sources by limiting the parameter space available for ion source optimization. Previous studies have shown that the transition from stable to unstable plasma regime is strongly influenced by the magnetic field structure, especially the minimum field value inside the magnetic trap (Bmin). This work focuses to study the role o…

Spoken-Word Segmentation and Dyslexia

2002

We used magnetoencephalography to elucidate the cortical activation associated with the segmentation of spoken words in nonreading-impaired and dyslexic adults. The subjects listened to binaurally presented sentences where the sentence-ending words were either semantically appropriate or inappropriate to the preceding sentence context. Half of the inappropriate final words shared two or three initial phonemes with the highly expected semantically appropriate words. Two temporally and functionally distinct response patterns were detected in the superior temporal lobe. The first response peaked at approximately 100 msec in the supratemporal plane and showed no sensitivity to the semantic appr…

Audiovisual processing of Chinese characters elicits suppression and congruency effects in MEG

2019

Learning to associate written letters/characters with speech sounds is crucial for reading acquisition. Most previous studies have focused on audiovisual integration in alphabetic languages. Less is known about logographic languages such as Chinese characters, which map onto mostly syllable-based morphemes in the spoken language. Here we investigated how long-term exposure to native language affects the underlying neural mechanisms of audiovisual integration in a logographic language using magnetoencephalography (MEG). MEG sensor and source data from 12 adult native Chinese speakers and a control group of 13 adult Finnish speakers were analyzed for audiovisual suppression (bimodal responses…

Physical activity and aerobic fitness show different associations with brain processes underlying anticipatory selective visuospatial attention in ad…

2021

ABSTRACTUnderlying brain processes of exercise-related benefits on executive functions and the specific contribution of physical activity vs. aerobic fitness are poorly understood, especially during adolescence. We explored whether and how physical activity and aerobic fitness are associated with selective attention and the oscillatory dynamics induced by an anticipatory spatial cue. Further, we studied whether the link between physical exercise level and cognitive control in adolescents is mediated by the task-related oscillatory activity. Magnetoencephalographic alpha oscillations during a modified Posner’s cueing paradigm were measured in 59 adolescents (37 females and 22 males, 12 to 17…

Modeling optical constants from the absorption of organic thin films using a modified Lorentz oscillator model

2022

Optical constants of organic thin films can be evaluated using the Lorentz oscillator model (LOM) which fails to fit inhomogeneously broadened absorption of highly concentrated molecular films. In modified LOM (MLOM), the inhomogeneous broadening is implemented through a frequency-dependent adjustable broadening function. In this work, we evaluate the optical constants of rhodamine 6G doped poly-vinyl alcohol thin films with varying doping concentration (including also extensively high concentrations) using MLOM, which outperforms LOM by showing a better agreement with the experimental results. Our proposed method provides a way to accurately determine optical constants of isotropic organic…

Exploring Oscillatory Dysconnectivity Networks in Major Depression During Resting State Using Coupled Tensor Decomposition

2022

Dysconnectivity of large-scale brain networks has been linked to major depression disorder (MDD) during resting state. Recent researches show that the temporal evolution of brain networks regulated by oscillations reveals novel mechanisms and neural characteristics of MDD. Our study applied a novel coupled tensor decomposition model to investigate the dysconnectivity networks characterized by spatio-temporal-spectral modes of covariation in MDD using resting electroencephalography. The phase lag index is used to calculate the functional connectivity within each time window at each frequency bin. Then, two adjacency tensors with the dimension of time frequency connectivity subject are constr…

The introduction process of the groupware product

2005

Groupware support for operational management

2003

Do opposite ends of same factors underlie life satisfaction vs. depressive symptoms among older people?

2021

Abstract Background Although depressive symptoms are more common among older than younger age groups, life satisfaction tends to remain stable over the life course, possibly because the underlying factors or processes differ. Aim To study whether the factors that increase the likelihood of high life satisfaction also decrease the likelihood of depressive symptoms among older people. Methods The data were a population-based probability sample drawn from community-dwelling people aged 75, 80, and 85 years (n = 1021). Participants’ life satisfaction was measured with the Satisfaction with Life Scale and depressive symptoms with the Centre for Epidemiologic Studies Depression Scale (CES-D). Phy…

Identifying Oscillatory Hyperconnectivity and Hypoconnectivity Networks in Major Depression Using Coupled Tensor Decomposition

2021

AbstractPrevious researches demonstrate that major depression disorder (MDD) is associated with widespread network dysconnectivity, and the dynamics of functional connectivity networks are important to delineate the neural mechanisms of MDD. Cortical electroencephalography (EEG) oscillations act as coordinators to connect different brain regions, and various assemblies of oscillations can form different networks to support different cognitive tasks. Studies have demonstrated that the dysconnectivity of EEG oscillatory networks is related with MDD. In this study, we investigated the oscillatory hyperconnectivity and hypoconnectivity networks in MDD under a naturalistic and continuous stimuli…