Wyniki wyszukiwania - Biblioteka Nauki

1

Changes in Distortion Product Otoacoustic Emission Caused by Contralateral Broadband Noise

100%

Ozimek E. , Wicher A.

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tom Vol. 39, No. 1

125--138

EN

The main purpose of this investigation was to measure the effect of contralateral acoustic stimulation (CAS) on distortion product otoacoustic emission (DPOAE) in twenty human ears, for a ratio of primary tones f2/f1 = 1.22 and a wide frequency range of f2 (1.4–9 kHz), for two intensity levels of primary tones (L1 = 60 dB SPL; L2 = 50 dB SPL and L1 = 70 dB SPL; L2 = 60 dB SPL) and two intensity levels of CAS (50 and 60 dB SPL). It was found that in the presence of CAS, in the majority of cases the DPOAE level decreased (suppression), but it might also increase (enhancement) or remain unchanged depending on the frequency. The mean suppression level of the component of the frequency fDP = 2f1 − f2 might be approximated by a linearly decreasing function of the f2 frequency of primary tones. The slope of this function was negative and increased with an increase of the contralateral stimulation level. The higher was the contralateral noise level the greater was the suppression. For the fDP level below about 15 dB SPL, suppression was observed in a substantial number of measurement cases (in about 85% of all measured cases on average). When the fDP level was higher than 15 dB SPL, only suppression (not enhancement) was observed.

2

Zwiększanie dostępności dla roślin fosforu obecnego w glebie metodami biologicznymi

100%

Kurek E. , Ozimek E.

Postępy Nauk Rolniczych

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2008

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tom 60

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nr 2

3

Binaural perception of amplitude and frequency modulated signals

100%

Ozimek E. , Wicher A.

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tom Vol. 25, no. 2

131-145

EN

The investigations focused on the binaural perception of amplitude modulated (AM) and frequency modulated (FM) signals. They are comprised of two experiments. In the first experiment binaurally perceived (matched) modulation depth for AM signals was determined under diotic conditions (i.e. for the same values of modulation depth coefficient, m, presented to the left (ml) and right (mr) ears) and under dichotic conditions (i.e. for different values of these coefficients ml [różne od] mr). The measurements were made for the interaural differences in modulation depth coefficient [delta]m, changing from 0 to 100% and a few selected modulating frequencies (4, 64 and 128 Hz) and carrier frequencies (250 and 1000 Hz). In the second experiment binaurally perceived (matched) frequency deviation of FM signals was determined under diotic conditions (i.e. for the same values of frequency deviation, [delta]f, presented to the left (delta f_l) and right (delta fr) ear (delta fl =delta fr) and under dichotic conditions (i.e. for different values of this deviation (delta fl delta delta fr)). The measurements were made for the interaural differences of frequency deviation changing from 0 to 20 Hz; a few selected modulating frequencies (32, 64 and 128 Hz) and carrier frequencies (500 and 1000 Hz). It was found in Experiment I that for small interaural differences in modulation depth, delta m, the binaurally perceived modulation depth, m, is equal to the arithmetic mean of the depths presented to the left and right ears, whereas for large values of delta m, the value of m is smaller than the mean. The results of Experiment II revealed that the binaurally perceived frequency deviation is a linear function of interaural differences of this deviation and is equal to the arithmetic mean of deviations presented to the left and right ears.

4

Binauralna percepcja sygnałów FM w przypadku miedzyusznej różnicy częstotliwości modulacji]

100%

Wicher A. , Ozimek E.

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tom Vol. 83, nr 27

109-112

EN

The main objective of this study was to determine the binaural interaction in modulation frequency domain for FM signals. The results have show that for interaural differences in modulation frequency, except for fast frequency deviation, the subjects perceived additionally slow frequency deviation with rate corresponding to interaural modulation frequency. The range of this deviation depended on interaural differences in modulation rate.

5

Speech Intelligibility in Rooms with and without an Induction Loop for Hearing Aid Users

100%

Kociński J. , Ozimek E.

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2015

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tom Vol. 40, No. 1

51--58

EN

The paper presents the results of sentence and logatome speech intelligibility measured in rooms with induction loop for hearing aid users. Two rooms with different acoustic parameters were chosen. Twenty two subjects with mild, moderate and severe hearing impairment using hearing aids took part in the experiment. The intelligibility tests composed of sentences or logatomes were presented to the subjects at fixed measurement points of an enclosure. It was shown that a sentence test is more useful tool for speech intelligibility measurements in a room than logatome test. It was also shown that induction loop is very efficient system at improving speech intelligibility. Additionally, the questionnaire data showed that induction loop, apart from improving speech intelligibility, increased a subject’s general satisfaction with speech perception.

6

Intelligibility of speech processed by a spectral contrast enhancement procedure and a binaural procedure

80%

Sęk A. , Skrodzka E. , Ozimek E. , Wicher A.

Archives of Acoustics

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2004

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tom Vol. 29, no. 1

25-34

EN

The study reported was undertaken as an attempt to improve the intelligibility of selected speech signals (numerical test) masked by a speech-shaped noise, by a proposed algorithm of the speech signal processing based on the spectral contrast enhancement and binaural procedure. The spectral contrast enhancement involved the transformation of the speech signal spectrum to achieve an increase in the level of the amplitude between subsequent minima and maxima of individual formants. The binaural procedure involved the determination of the interaural time difference (ITD) and the interaural intensity difference (IID) in order to select and enhance the fragments reaching the listener from the front. The intelligibility of speech processed by the algorithm was compared to that of the unprocessed speech for different spatial separations between the signal and the noise sources and for a few signal to noise ratios. The results have shown that the intelligibility of the speech presented against the noise significantly depends on the angle between the directions of the signal and the noise. The intelligibility of speech is much larger when the noise and the speech reach the observer from different directions, i.e. when their sources are spatially separated. In general, the algorithm improves the intelligibility of numerical tests presented at the background of the noise by a few percent and the greatest improvement has been observed for low signal to noise ratios. The algorithm performance was different for each hearing impaired subject with binaural hearing loss. To get an objective assessment of the algorithm performance it should be optimised and tested on a larger group of subjects for more diverse sound material.

7

Auditory filters in sensorineural hearing impaired subjects

80%

Skrodzka E. B. , Wicher A. , Ozimek E. , Sęk A. P.

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tom Vol. 27, no. 3

159-174

EN

The study is devoted to determination of the shape of the auditory filters in subjects with sensorineural hearing loss. Apart from the classical sensorineural hearing loss, changes in the auditory filter shapes have been analysed in the subject diagnosed with dead regions. The dead region is an area on the basilar membrane over which the functioning of the inner hair cells and/or neurones innervating them has ceased. This type of hearing impairment means that the information on the sounds whose frequencies correspond to the dead region of the basilar membrane are to a very limited degree if at all, transmitted to higher levels of the auditory path. This transmission, if happens, is performed through the auditory filters at the centre frequency other than that of the signal. This phenomenon and the fact that in the dead region the hearing loss is theoretically infinite, affect the transmittance of the auditory filters. Results of the study reported here have shown that in general, the subjects with sensorineural hearing loss develop broadening of the auditory filter accompanied by reducing of its dynamics. This fact explains a considerable decrease in speech intelligibility presented at a background of a noise. In the subject with the dead regions the broadening of the filters was the greatest in the region of the dead one. The results also indicate the lack of correlation between the shape and width of the auditory filter and the shape of the audiogram.

8

Efekt zastosowania chinskiego bionawozu JUWEI C.B.I. na plon kukurydzy uprawianej na glebie lekkiej w warunkach Pomorza Zachodniego

71%

Kurek E. , Niedzwiecki E. , Protasowicki M. , Slomka A. , Ozimek E.

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nr 3

121-128

9

Czynniki ograniczajace efektywnosc biopreparatu 'Juwei' CBI w warunkach glebowych Pomorza Zachodniego

71%

Kurek E. , Niedzwiedzki E. , Protasowicki M. , Slomka A. , Ozimek E.

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2006

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tom 515

227-239

PL

Na glebie lekkiej typowej dla Pomorza Zachodniego przeprowadzono doświadczenia poletkowe nad efektywnością chińskiego biopreparatu „JUWEI” CBI do stymulowania wzrostu kukurydzy (2002 - 2004) i ziemniaków (2003 - 2005). Preparat ten zawiera dwa szczepy bakterii z rodzaju Bacillus, charakteryzujące się między innymi zdolnością do rozpuszczania fosforanów nieorganicznych (B. megatherium i B. mucilaginosus) i wiązania N₂ (B. mucilaginosus). Biopreparat zastosowano zgodnie z zaleceniami producenta. Gleba na poletkach pod testowanymi roślinami różniła się właściwościami fizykochemicznymi, zwłaszcza pHKCl (4,9 - 7,1), zawartością dostępnego P (4,9 - 24,5 mg·100 g⁻¹) i K (7,5 - 12,3 mg·100 g⁻¹), ogólną zawartością C (0,67 - 0,91%) i N (0,06 - 0,20%), lecz zawierała wysoką i zbliżoną liczebność bakterii rozpuszczających fosforany i wiążących N₂ (1·10⁷·g⁻¹ s.m. gleby). Nie stwierdzono statystycznie istotnego zwiększenia plonów testowych roślin, zawartości w nich P i K oraz zawartości w glebie dostępnego P i K w poszczególnych latach pomimo zróżnicowanych właściwości fizykochemicznych gleby pod uprawami. Analizy mikrobiologiczne wykazały, że zarówno w glebie wolnej od korzeni, jak też w strefie korzeniowej roślin na poletkach traktowanych „JUWEI” CBI nie zwiększyła się liczebność mikroorganizmów o cechach fizjologicznych szczepów wprowadzonych z biopreparatem. Uzyskane wyniki sugerują, że brak efektywności biopreparatu można wiązać ze zbyt niską liczebnością bakterii wprowadzonych do gleby z opłaszczonymi nim ziarniakami i bulwami. Przy zajętej niszy ekologicznej przez szczepy rodzime, nie miały szans na zasiedlenie i rozwój.

EN

Biofertilizer „JUWEI” CBI containing two bacteria, Bacillus megatherium and B. mucilaginosus, capable to mobilizing phosphate and potassium from soil minerals and fixing N₂ has been manufactured in China since 1988. Field experiments conducted by Agricultural Institutes in Gaocheng and Langfang prefectures during 1990 - 1993 showed that after application of biofertilizer the average yields of grain crops and vegetables increased by 10% and by 20 - 30%, respetively. Plot experiments on the effect of „JUWEI” CBI (used according to the manufacture’s instructions) on the growth and yielding of maize and potato were conducted during 2002 - 2004 and 2003 - 2005, respectively, at Lipnik Experimental Station, Agricultural University of Szczecin. Physico-chemical properties of the soil on plots planted with tested plants differed in regard to pHKCl values (4.9 - 7.1), content of available P (4.9 - 24.5 mg·100 g⁻¹ soil) and K (7.5 - 12.3 mg·100 g⁻¹ soil), total content of C (0.67 - 0.91%) and N (0.06 - 0.20%). However, the number of bacteria capable to mobilizing P and fixing N₂ isolated from the soil were high (1·10⁷·g⁻¹ soil DM) and there was no significant differences between the plots. Statistical data analysis indicated that the treatment of plants with biofertilizer did not affect the yield, concentration of available P and K in soil, or the concentration of these elements in plant tissues. Microbial analysis of root-free and rhizospheric soil showed that there was no difference in the number of bacteria of the same phenotype as the bacteria introduced with biofertilizer between the soil sampled from control plots and that treated with „JUWEI” CBI. Lack of the biofertilizer „JUWEI” effectiveness could be due to a low number of microorganisms introduced with it into soil. The organisms had no chance to proliferate in the soil used to experiments, because their ecological niche had already been occupied by native microorganisms.