Effect of Harmonicity on the Detection of a Signal in a Complex Masker and on Spatial Release from Masking

The amount of masking of sounds from one source (signals) by sounds from a competing source (maskers) heavily depends on the sound characteristics of the masker and the signal and on their relative spatial location. Numerous studies investigated the ability to detect a signal in a speech or a noise masker or the effect of spatial separation of signal and masker on the amount of masking, but there is a lack of studies investigating the combined effects of many cues on the masking as is typical for natural listening situations. The current study using free-field listening systematically evaluates the combined effects of harmonicity and inharmonicity cues in multi-tone maskers and cues resulting from spatial separation of target signal and masker on the detection of a pure tone in a multi-tone or a noise masker. A linear binaural processing model was implemented to predict the masked thresholds in order to estimate whether the observed thresholds can be accounted for by energetic masking in the auditory periphery or whether other effects are involved. Thresholds were determined for combinations of two target frequencies (1 and 8 kHz), two spatial configurations (masker and target either co-located or spatially separated by 90 degrees azimuth), and five different masker types (four complex multi-tone stimuli, one noise masker). A spatial separation of target and masker resulted in a release from masking for all masker types. The amount of masking significantly depended on the masker type and frequency range. The various harmonic and inharmonic relations between target and masker or between components of the masker resulted in a complex pattern of increased or decreased masked thresholds in comparison to the predicted energetic masking. The results indicate that harmonicity cues affect the detectability of a tonal target in a complex masker

A New Automated Determination of Uric Acid

Peer Reviewe

Densitometric determination of catecholamine metabolites and 5-hydroxy-indoleacetic acid after two-dimensional thin-layer chromatography on cellulose

A quantitative two-dimensional chromatographic determination for the catecholamine metabolites vanilglycolic (vanilmandelic) acid, vanilacetic acid, vanillactic acid and vanilglycol is described. The method can also be used for the determination of 5-hydroxy-indoleacetic acid. The analytical procedure consists of the following steps: 1. extraction (after enzymatic hydrolysis when vanilglycol has to be determined); 2. two-dimensional chromatography on thin-layer cellulose; 3. quantitative evaluation of the spots by means of a chromatogram scanner. Standard deviations, recoveries, 24-h excretions in 10 normal adults and results in 10 patient suffering from neurogenic tumors are given. Some of the merits of a multi-component determination of the type described here for the clinical diagnosis of secreting neurogenic and serotonin-producing tumors are discussed

Investigation of Reference Values of Components of Cerebrospinal Fluid

Peer Reviewe

Semantics and Implementation of a Generalized forall Statement for Parallel Languages

In this paper we present a generalized forall statement for parallel languages. The forall statement occurs in many (data) parallel languages and specifies which computations can be performed independently. Many different definitions of such a construct can be found in literature, with different conditions and execution models. We will show how forall constructs of a wide class of parallel languages can be mapped to this generalized forall statement. In addition, the forall statement we propose has the ability to spawn more complex independent activities than can be found in these languages

The Reference Model Architecture for MPEG Spatial Audio Coding

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A formal approach to the compilation of data parallel languages

In this paper we describe an approach to the compilation of data-parallel programming languages based on a formally defined intermediate language, called V-cal . The calculus V-cal was designed to represent the semantics of data management and control primitives found in data-parallel languages and allows to describe program transformations and optimizations as semantics preserving rewrite rules