Localization of Acoustic Signals Used in Sound Emitters at Pedestrian Crosswalks

This study aimed at determining an optimal acoustic signal, which could be used in sound emitters at blind and visually impaired enabled pedestrian crosswalks. Two signals were identified from among groups of tested signals on the basis of psychoacoustic tests. These two signals met the following standard requirements: TR signal - a signal with a triangular temporal envelope and a sinusoidal carrier and RC signal - a signal with a rectangular temporal envelope and a rectangular carrier, both with a basic frequency of 880 Hz, repeated periodically with a frequency of 5 Hz. The ability to localize was tested by a modified method of angle of directional hearing acuity in which the two alternative forced choice adaptation procedure was used. The test signals were emitted against the background of traffic noise and the ratio of the useful signal (65 dB SPL) to noise (75 dB SPL) was (-10 dB). The tests were conducted on 8 subjects with normal hearing (5 women and 3 men), aged 22-37 years. Following statistical analysis it was found that: individual subjects' responses differed considerably with respect to angle of direction hearing acuity values, localization is most difficult at the angles of 90° and 270°, worse localization for trams noise were stated, RC signals are better localized than TR signals

Wpływ dodatku enyzmów na pienistość przetworów z białka jaj

Effects of pancreatin, trypsin, Amylopol P (preparation from Asp. oryzae), and alpha-amylase on the whipping properties of frozen, pan dried, and spray-dried albumen were investigated. Pancreatin markedly influenced a foamability of the all mentioned products, while the others enzymes affected a foamability of froz(m and or pan-dried eggwhite only. The changes in glycoproteins of egg-white due to pancreatin and presumable action of alpha-amylase are discussed

Localization of Sound Sources in Normal Hearing and in Hearing Impaired People

This article presents results of investigations of the angle of directional hearing acuity (ADHA) as a measure of the spatial hearing ability with a special emphasis on people with hearing impairments. A modified method proposed by Zakrzewski has been used – ADHA values have been determined for 8 azimuths in the horizontal plane at the height of the listeners’ head. The two-alternative-forced-choice method (2AFC), based on a new system of listeners’ responses (left – right instead of no difference – difference in location of sound sources) was the procedure used in the experiment. Investigations were carried out for two groups of subjects: normal hearing people (9 persons) and hearing impaired people (sensorineural hearing loss and tinnitus – 9 persons). In the experiment different acoustic signals were used: sinu- soidal signals (pure tones), 1/3 octave noise, amplitude modulated 1/3 octave noise, CCITT speech and traffic noises and signals corresponding to personal character of tinnitus for individual subjects. The results obtained in the investigations showed, in general, a better localization of the sound source for noise type signals than those for tonal signals. Inessential differences exist in ADHA values for particular signals between the two groups of subjects. On the other hand, significant differences for tinnitus signals and traffic noise signals were stated. A new system of listeners’ responses was used and appeared efficient (less dispersion of results compared to the standard system)

Localization of Acoustic Signals Used in Sound Emitters at Pedestrian Crosswalks

This study aimed at determining an optimal acoustic signal, which could be used in sound emitters at blind and visually impaired enabled pedestrian crosswalks. Two signals were identified from among groups of tested signals on the basis of psychoacoustic tests. These two signals met the following standard requirements: TR signal - a signal with a triangular temporal envelope and a sinusoidal carrier and RC signal - a signal with a rectangular temporal envelope and a rectangular carrier, both with a basic frequency of 880 Hz, repeated periodically with a frequency of 5 Hz. The ability to localize was tested by a modified method of angle of directional hearing acuity in which the two alternative forced choice adaptation procedure was used. The test signals were emitted against the background of traffic noise and the ratio of the useful signal (65 dB SPL) to noise (75 dB SPL) was (-10 dB). The tests were conducted on 8 subjects with normal hearing (5 women and 3 men), aged 22-37 years. Following statistical analysis it was found that: individual subjects' responses differed considerably with respect to angle of direction hearing acuity values, localization is most difficult at the angles of 90° and 270°, worse localization for trams noise were stated, RC signals are better localized than TR signals

Ciężar ogólny i ciężar właściwy jako wskaźniki przetłuszczenia i umięśnienia tuszek kaczek brojlerów

Statistically significant corellations (p < 0,01) between the specific gravity and total weight of broiler duck carcasses on the one hand and the content of fat in their breast and thigh muscles as well as in skin with subcutaneous fat on the other were determined. The correlations may be applied in estimating the level of fat in ducks. No correlations were found between the carcasses specific gravity and the level of muscle content in them.Badania przeprowadzono na 30 tuszkach kaczek brojlerów ubijanych w wieku ok. 8 tygodni. Ciężar właściwy (kg/dcm³) wypatroszonych tuszek, bez głowy i łap obciętych w stawie skokowym, oznaczano na podstawie różnicy ich ciężarów w powietrzu i w wodzie. Tuszki poddawano dysekcji wypreparowując mięśnie piersiowe, mięśnie udowe oraz skórę z tłuszczem podskórnym. Te dysekcyjne elementy ważono, a następnie oznaczano w nich zawartość tłuszczu. Stwierdzono bardzo istotne, ujemne korelacje między ciężarem właściwym tuszek, a zawartością tłuszczu w mięśniach piersiowych i udowych oraz ciężarem skóry i tłuszczu podskórnego. Wykazano również istotną, dodatnią korelację między ciężarem ogólnym, a zawartością tłuszczu w mięśniach udowych i w skórze z tłuszczem podskórnym tuszek kaczek. Podano propozycje wykorzystania wymienionych wyżej zależności dla praktycznej, obiektywnej oceny stopnia przetłuszczenia kaczek. Nie znaleziono istotnych korelacji między ciężarem właściwym a umięśnieniem tuszek kaczek brojlerów