Acoustic Analyses of Developmental Changes and Emotional Expression in the Preverbal Vocalizations of Infants

The nonverbal vocal utterances of seven normally hearing infants were studied within their first year of life with respect to age- and emotion-related changes. Supported by a multiparametric acoustic analysis it was possible to distinguish one inspiratory and eleven expiratory call types. Most of the call types appeared within the first two months; some emerged in the majority of infants not until the 5th (“laugh”) or 7th month (“babble”). Age-related changes in acoustic structure were found in only 4 call types (“discomfort cry,” “short discomfort cry,” “wail,” “moan”). The acoustic changes were characterized mainly by an increase in harmonic-to-noise ratio and homogeneity of the call, a decrease in frequency range and a downward shift of acoustic energy from higher to lower frequencies. Emotion-related differences were found in the acoustic structure of single call types as well as in the frequency of occurrence of different call types. A change from positive to negative emotional state was accompanied by an increase in call duration, frequency range, and peak frequency (frequency with the highest amplitude within the power spectrum). Negative emotions, in addition, were characterized by a significantly higher rate of “crying,” “hic” and “ingressive vocalizations” than positive emotions, while positive emotions showed a significantly higher rate of “babble,” “laugh,” and “raspberry.”     

Bacterial Lux-Fluoro test for biological assessment of pollutants in water samples from urban and rural origin

During the 20th century, population growth and urbanization, together with changes in production and consumption, have placed unprecedented demands on the quality of water. The ongoing extraordinary economic growth, industrialization, and urbanization of many developing countries results in widespread water pollution from agricultural, industrial, and domestic sources. In consequence, people consume contaminated drinking water, thereby increasing the risk of exposure not only to infectious and parasitic disease but also to a growing volume of genotoxic and cytotoxic chemicals. In light of these trends, new, rapid and low-cost approaches are urgently needed to assess the quality of water supplies. Because of their simplicity and sensitivity, bacterial tests play an important role in the detection and screening of genotoxins or cytotoxins in water. Thus, the bacterial Lux-Fluoro test, which is a combination of two bioassays that simultaneously measure the genotoxicity (SOS-Lux test) and the cytotoxicity (LAC-Fluoro test), was used to identify polluted water from samples of rural and urban sources, collected from 10 different locations in the Punjab rivers’ basin. We identified at least three samples from rural origin having a high cytotoxic potential. The highest toxicity was found for the sample obtained from a draining canal collecting runoff water from the fields. The two other highly contaminated samples identified were taken from two ponds of different villages. The water samples obtained from the Ravi river and from the water tap in a suburb of the megacity Lahore showed no sign of genotoxicity or cytotoxicity. Seven control samples with differing genotoxic and cytotoxic potency were shown for comparison.     

Photoluminescence properties of Co-doped ZnO nanocrystals

We performed photoluminescence experiments on colloidal, Co²⁺-doped ZnO nanocrystals in order to study the electronic properties of Co²⁺ in a ZnO host. Room temperature measurements showed, next to the ZnO exciton and trap emission, an additional emission related to the Co²⁺ dopant. The spectral position and width of this emission does not depend on particle size or Co²⁺ concentration. At 8 K, a series of ZnO bulk phonon replicas appear on the Co²⁺-emission band. We conclude that Co²⁺ ions are strongly localized in the ZnO host, making the formation of a Co²⁺d-band unlikely. Magnetic measurements revealed a paramagnetic behaviour.     

Isotachophoretische Bestimmung der B-Vitamine im ng-Bereich unter Verwendung kationischer Spacerionen

Ohne Zusammenfassung

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Isotachophoretic determination of vitamins B in the ng-range using kationic spacer ions

     

A multilevel algorithm for the biharmonic problem

Summary A finite element discretization of the mixed variable formulation of the biharmonic problem is considered. A multilevel algorithm for the numerical solution of the discrete equations is described. Convergence is proved under the assumption ofH ³-regularity.     

Penrose tilings as coverings of congruent decagons

The open problem of tiling theory whether there is a single aperiodic two-dimensional prototile with corresponding matching rules, is answered for coverings instead of tilings. We introduce admissible overlaps for the regular decagon determining only nonperiodic coverings of the Euclidean plane which are equivalent to tilings by Robinson triangles. Our work is motivated by structural properties of quasicrystals.