University of Oldenburg

About: University of Oldenburg is a education organization based out in Oldenburg, Niedersachsen, Germany. It is known for research contribution in the topics: Population & Catalysis. The organization has 6868 authors who have published 16858 publications receiving 429788 citations. The organization is also known as: Carl von Ossietzky University of Oldenburg & Carl von Ossietzky Universität Oldenburg.

Revision, extension, and evaluation of a binaural speech intelligibility model.

Abstract: This study presents revision, extension, and evaluation of a binaural speech intelligibility model (Beutelmann, R, and Brand, T (2006) J Acoust Soc Am 120, 331-342) that yields accurate predictions of speech reception thresholds (SRTs) in the presence of a stationary noise source at arbitrary azimuths and in different rooms The modified model is based on an analytical expression of binaural unmasking for arbitrary input signals and is computationally more efficient, while maintaining the prediction quality of the original model An extension for nonstationary interferers was realized by applying the model to short time frames of the input signals and averaging over the predicted SRT results Binaural SRTs from 8 normal-hearing and 12 hearing-impaired subjects, incorporating all combinations of four rooms, three source setups, and three noise types were measured and compared to the model's predictions Depending on the noise type, the parametric correlation coefficients between observed and predicted SRTs were 080-093 for normal-hearing subjects and 059-080 for hearing-impaired subjects The mean absolute prediction error was 3 dB for the mean normal-hearing data and 4 dB for the individual hearing-impaired data 70% of the variance of the SRTs of hearing-impaired subjects could be explained by the model, which is based only on the audiogram

Non-invasive Brain Stimulation: A Paradigm Shift in Understanding Brain Oscillations.

Abstract: Cognitive neuroscience set out to understand the neural mechanisms underlying cognition. One central question is how oscillatory brain activity relates to cognitive processes. Up to now, most of the evidence supporting this relationship was correlative in nature. This situation changed dramatically with the recent development of non-invasive brain stimulation (NIBS) techniques, which open up new vistas for neuroscience by allowing researchers for the first time to validate their correlational theories by manipulating brain functioning directly. In this review, we focus on transcranial alternating current stimulation (tACS), an electrical brain stimulation method that applies sinusoidal currents to the intact scalp of human individuals to directly interfere with ongoing brain oscillations. We outline how tACS can impact human brain oscillations by employing different levels of observation from non-invasive tACS application in healthy volunteers and intracranial recordings in patients to animal studies demonstrating the effectiveness of alternating electric fields on neurons in vitro and in vivo. These findings likely translate to humans as comparable effects can be observed in human and animal studies. Neural entrainment and plasticity are suggested to mediate the behavioral effects of tACS. Furthermore, we focus on mechanistic theories about the relationship between certain cognitive functions and specific parameters of brain oscillaitons such as its amplitude, frequency, phase and phase coherence. For each of these parameters we present the current state of testing its functional relevance by means of tACS. Recent developments in the field of tACS are outlined which include the stimulation with physiologically inspired non-sinusoidal waveforms, stimulation protocols which allow for the observation of online-effects, and closed loop applications of tACS.

Esterification of a Fatty Acid by Reactive Distillation

Abstract: A reactive distillation process for the production of decanoic acid methyl esters by esterification of the fatty acid decanoic acid with methanol is presented. The reaction has been catalyzed heter...

Speech intelligibility prediction in hearing‐impaired listeners based on a psychoacoustically motivated perception model

Abstract: Sensorineural hearing‐impaired listeners suffer severely from deterioration in the processing and internal representation of acoustic signals. In order to understand this deterioration in detail, a numerical perception model was developed which is based on current functional models of the signal processing in the auditory system. To test this model, the individual’s speech intelligibility in quiet and in noise was predicted. The primary input parameter of the model is the precisely measured audiogram of each listener. In a refined version of the model, additional input parameters are derived from predicting the individual’s temporal forward masking and notched‐noise measurements with the same model assumptions. The predictions of the perception model were compared with those of the articulation index (AI) and the speech transmission index (STI). The accuracy of prediction with the perception model is in the same range as with the AI and the STI. The model does not require a calibration function and has th...

alpha-synuclein is developmentally expressed in cultured rat brain oligodendrocytes.

Abstract: Although a neuronal protein, α-synuclein is a major component of glial cytoplasmic inclusions (GCIs) in oligodendrocytes of multiple system atrophy (MSA) brains. Because α-synuclein has not been identified in oligodendrocytes of normal brains, we examined cultured rat brain oligodendrocytes during in vitro development and showed that α-synuclein mRNA and protein are present in cultured oligodendrocytes. The expression of α-synuclein was developmentally regulated; it increased to peak levels at 2 or 3 days in culture but declined thereafter. Indirect immunofluorescence further shows that α-synuclein was localized predominantly in cell bodies and primary processes of oligodendroglia. Thus, GCIs may be a consequence of altered rather than de novo expression of α-synuclein in MSA oligodendrocytes. J. Neurosci. Res. 62:9–14, 2000. © 2000 Wiley-Liss, Inc.