The purpose of this study was to use previously recorded Spanish trisyllabic words tested on adults in the measurement of the speech recognition threshold of Spanish-speaking children in order to (a) determine the words' appropriateness when testing children and (b) compare psychometric functions between adults and children. A selection of 28 frequently used trisyllabic words was chosen from previously recorded samples of male and female adult native speakers of Spanish. These words were then presented to 20 native Spanish-speaking children with normal hearing between the ages of 4 and 8 years. The words were presented starting at -5 dB HL and ascended in 5 dB increments until the presentation level reached 15 dB HL. Using logistic regression, psychometric functions were calculated for each word. Resulting pediatric thresholds were found to be 8.7 dB higher for male talkers and 11.0 dB higher for female talkers than previously reported adult thresholds. These results indicate a clinically significant threshold difference between pediatric and adult populations. Future research should be conducted to measure the speech recognition threshold (SRT) in children of varying ages to determine the age at which the SRT approximates with adult performance.

Three continuously stirred tank reactors (CSTR) were operated in semi continuous mode treating swine waste using anaerobic digestion. The reactors were used to test the effect of solid retention time (SRT) on CH4 yield, total ammonia nitrogen (TAN) concentrations, % volatile solids (VS), chemical oxygen demand (COD) and volatile fatty acids (VFA) removal, readily biodegradable COD concentration and the denitrification potential for the effluent in a biological nutrient removal (BNR) system. During Phase I of the study, the three reactors were operated at the same 28 day SRT for 16 weeks. SRTs were then changed during the 12 week Phase II period. The SRTs studied were 14, 21 and 28 days, with the same organic loading rate (OLR) of 1.88 ± 0.2 kg VS/ m3-day. The reactor with the lowest SRT (14 days) had the highest VS and VFA removal at 73.6 and 67.6% and lowest TAN concentration at 0.78 g NH4+-N/L, followed by the 21 day and 28 day reactors. This was likely due to the fast microbial growth rates and substrate utilization rates in this reactor compared with the other two. The 14 day reactor had the highest CH4 yield at 0.33 m3CH4/kg VS added and readily biodegradable COD concentration at 0.93 COD/L. The variations in CH4 yield and readily biodegradable COD concentrations between the three reactors were not statistically significant. Denitrification potential for the reactors was 1.20, 0.73 and 0.56 g COD/g N for 14, 21 and 28 day reactors, respectively, and the differences were statistically significant. None of the reactors achieved a denitrification potential of 5 g COD/g N, the amount required to use effluent of anaerobically digested swine waste as an internal carbon source in a BNR. This was attributed to operating conditions such as freezing and thawing of the raw swine waste that maximized CH4 yield and lowered the readily biodegradable COD concentration. In addition the 14 day reactor had low TAN concentrations thus increasing the denitrification potential of the centrate from that reactor.

At Kungsberget ski-resort in Gävleborg county all wastewater produced at the facility is treated on-site. The treatment takes place at their own wastewater treatment plant in a so-called Sequence Batch Reactor (SBR), which has been in operation for about a year before this study. Kungsberget AB is currently in charge of the facility but their goal is to hand responsibility over to Sandviken Energy AB. In order for this handover to occur Kungsberget has to produce three approved treatment results. This means that the concentrations of BOD7 needs to lie under 0.3 mg/l and total phosphorous under 10 mg/l in the effluent water for three consecutive samples. The results show momentaneous values. These limits are stated in the permit Kungsberget received from the Environmental Protection Division. Kungsberget has had problems with high and fluctuating phosphorous concentrations and therefore the transfer has not yet taken place. In this project several parameters have been analysed in order to obtain an overview of prevailing influent and effluent concentrations. Some of the parameters that have been analysed are; phosphorous, nitrogen, BOD7, suspended solids and pH. A lot of time and effort has been put into elucidating operational routines at the wastewater treatment plant (WWTP) and gaining knowledge from available literature regarding different parameters’ effect on treatment results.   Kungsberget has had problems adapting operating routines and reaching stable treatment results as the load is highly effected of seasonal fluctuation. This has not been taken into account earlier and the WWTP has been operated in the same manner all year around. Suggestions to how operating routines can be modified in to better meeting the needs have been produced and alternative treatment methods have been presented in the report. Two of the suggestions include biological phosphorous removal and adding carrier media to increase bacteria growth. An aerobic solids retention time has been calculated in order to evaluate whether nitrifying bacteria have enough time for grow and maintain a stable population. The calculation was carried out by measuring suspended solids and aeration time and the result was a solids retention time of approximately 6 days.

For nearly two decades researchers have been interested in identifying what specifically is learned when individuals learn a sequence (e.g., sequence of stimuli, sequence of motor movements, etc.). Despite extensive research in the area, considerable controversy remains surrounding the locus of learning. There are three main theories concerning the nature of spatial sequence learning: sequence learning is purely perceptual, sequence learning includes a motor component and sequence learning is based on stimulus-response (S-R) rules. The present studies sought to disentangle these theories by demonstrating that sequence learning has both a perceptual and motor component and that altering S-R rules alone disrupts sequence learning. Experiment 1 results fully supported this S-R rule theory of sequence learning. Experiment 2 results provided only partial support for this theory, though the data were also inconsistent with both of the other accounts.

Speech audiometry materials are essential for thorough audiological testing. One aspect of speech audiometry is evaluating an individual's speech recognition threshold (SRT). Recorded materials for SRT are available in many languages; however there are no widely published recorded SRT materials available in the Thai language. The goal of this study was to develop relatively psychometrically equivalent SRT materials for evaluating the hearing abilities of native speakers of the Thai language. To accomplish this, 90 commonly used bisyllabic Thai words were digitally recorded by a male and a female talker and evaluated by 20 native Thai listeners. Twenty-eight words with relatively steep and homogeneous psychometric function slopes were selected and adjusted to reduce threshold variability. These 28 selected words were digitally recorded onto compact disc to facilitate SRT testing for native Thai speakers.

The purpose of this study was to develop, digitally record, evaluate, and equate Mongolian monosyllabic and bisyllabic child-appropriate words which can be used in the measurement of word recognition scores and speech-reception threshold (SRT) in children who are native speakers of Mongolian. Based on data collected from a survey of Mongolian child language professionals, a subset of child-appropriate materials was adapted from a set of materials developed for Mongolian adults. Two lists of 50 monosyllabic words and four half-lists of 25 words each were developed for testing the word recognition abilities of Mongolian children. The developed lists and half-lists were found to be statistically equivalent in terms of audibility and psychometric slope, with average psychometric function slopes (at 50% intelligibility) of 6.41 %/dB for the male recordings and 5.84 %/dB for the female recordings. Given the structure and limitations of the study, a valid set of child-appropriate SRT materials could not be developed. It is likely that the inability to obtain a subset of SRT words was due in part to large differences between the mean PTA of the subjects and the threshold for 50% intelligibility, as well as the inability to represent most of the selected words pictographically. However the information gained from this study provides additional insight that may aid the future development of child-appropriate Mongolian SRT materials. Digital recordings of the resulting psychometrically equivalent child- appropriate speech audiometry materials are available on compact disc.

The Cannibal system, comprised of an activated sludge process integrated with a side stream anaerobic bioreactor, is capable of reducing excess sludge up to 60% compared to the conventional activated sludge process. The hydraulic retention time (HRT) in the Cannibal bioreactor and the interchange rate (the percent of sludge by mass interchanged between the activated sludge system and the bioreactor on daily basis) are the two important operational parameters in the optimization of the Cannibal process. This research was designed to investigate the effect of the Cannibal bioreactor hydraulic retention time and the interchange rate on the solids destruction in the system. The first phase of this study has looked at the effect of three different HRTs, 5 day, 7 day and 10 day. The interchange rate during phase I was 10%. The results showed that the 7 day HRT can be recommended as the minimum retention period for the Cannibal process. The 5 day HRT Cannibal system had some settling problems and high volatile fatty acid content compared to the 7 day HRT Cannibal system. The protein and polysaccharide tests showed that the Cannibal bioreactor is primarily involved in the release of biopolymers which are degraded in the aerobic environment. The second part of this study focused on the effect of the interchange rate (IR) on the solids destruction in the system. The interchange rates that were applied in the system were 15%, 10%, 7%, 5% and 4%.The HRT in the Cannibal bioreactor was 7 day. The results showed that the 10% interchange rate gave maximum solids destruction than the other interchange rates. This implies that 10% is an optimum IR for the Cannibal system. Apart from higher solids wastage, the 4% and 5% IR Cannibal systems had higher volatile fatty acid production. / Master of Science

INTRODUCTION. The Central Institute for the Deaf published Auditory Tests W-1 (CID W-1) spondaic wordlist was developed in the USA in 1947 and 1952. Certain American-English words contained in the wordlist are unfamiliar to many South Africans, even English first language (EFL) speakers, but particularly those who use English as a second language (ESL). Familiarity with spondaic words is one of the most important qualities of the test items used to determine Speech Recognition Threshold (SRT). OBJECTIVES. The aim of this study was to compare the SRT results obtained with the English South African Spondaic (SAS) wordlist developed by Durrant (2006) and the English CID W-1 spondaic wordlist when measuring the SRT of adult ESL speakers in South Africa. Method. Audiometric Pure Tone Average (PTA) and SRT measurements were obtained for 101 (197 ears) ESL participants with normal hearing or a minimal hearing loss <26 dBHL (mean age 33.3). PTA/SRT correlations were compared when using the SAS wordlist (groups one and two), as well as either the ‘less familiar’ CID W-1 (group one) or ‘more familiar’ CID W-1 (group two), in a mixed matched group design. RESULTS. A Pearson correlation analysis revealed a significant and positive correlation for all three wordlists. The Pearson correlation analysis revealed a strong PTA/SRT correlation when using the South African Spondaic (SAS) wordlist (right ear: 0.65; left ear 0.58) and the ‘more familiar’ words from the CID W-1 wordlist (right ear: 0.63; left ear: 0.56). The use of the ‘less familiar’ words from the CID W-1 wordlist revealed weak correlations (right ear: 0.30; left ear: 0.32). Paired sample T-tests indicated a statistically significantly stronger PTA/SRT correlation when the SAS wordlist was used, rather than either of the CID W-1 wordlists, at a 95% level of confidence. CONCLUSIONS. The use of the SAS wordlist yields a stronger PTA/SRT correlation than the use of the CID W-1 wordlist, when performing SRT testing as part of the speech audiometry battery on South African ESL speakers with normal hearing, or minimal hearing loss <26 dBHL. / Dissertation (MA)--University of Pretoria, 2014. / lk2014 / Speech-Language Pathology and Audiology / MA / Unrestricted

The purpose of this study was to develop digitally recorded speech audiometry materials in the Japanese language to evaluate Speech Reception Threshold (SRT) and speech discrimination. Trisyllabic words were used to evaluate the SRT and bisyllabic words were used for speech discrimination. Words were recorded by one native female talker and one native male talker who were judged as having standard Japanese dialects. Twenty native Japanese speakers between the ages of 20 and 32 were used as subjects to evaluate 69 trisyllabic words across 13 different intensity levels. The 25 trisyllabic words with the steepest psychometric function (%/dB) were selected for inclusion in the final CD. The final trisyllabic words were digitally adjusted so that the threshold of each word was equal to the mean PTA (3.42 dB HL) of all the subjects. The mean psychometric function (%/dB) at 50% for the trisyllabic words was 9.6 %/dB for the male talker and 7.7 %/dB for the female talker. The same 20 subjects were also used to evaluate 240 bisyllabic words across 10 different intensity levels. A logistic regression was used to obtain regression slopes for each of the 240 words. The 200 bisyllabic words with the steepest slope were selected for inclusion in the final CD. Four lists of 50 words each and eight half-lists of 25 words each were created from the selected bisyllabic words. A chi-square statistic revealed no significant differences among the lists or half-lists. The mean psychometric function at 50% for the bisyllabic lists and half-lists was 5.9 %/dB for the male talker and 5.2 %/dB for the female talker.

The development of digitally recorded speech audiometry materials in Mandarin Chinese has been limited to date. High quality materials proliferate in the English language and have been developed for other languages such as Brazilian Portuguese, Spanish, Japanese, Korean, French, Italian, Polish, and Russian. The aims of this study were to develop, digitally record, evaluate, and equate words and word lists in Mandarin Chinese to use for speech reception threshold testing and for speech discrimination testing. The words that were evaluated were chosen from a Chinese frequency usage dictionary. One native male and one native female talker recorded the words onto a compact disc. These words were then evaluated on 20 normally-hearing subjects, all of whom were natives of mainland China. Following the tests, the words and word lists were analyzed using logistic regression. For speech reception threshold testing, 24 Mandarin Chinese trisyllabic words with steep psychometric function slopes were selected. Their intensities were adjusted to match the mean subject pure-tone average of 3.0 dB HL. The mean slopes for these selected male and female trisyllabic words were 11.3 %/dB and 12.1 %/dB, respectively. For the speech discrimination testing, the 200 bisyllabic words with the steepest logistic regression slopes were divided among four psychometrically equivalent lists of 50 words each and eight half-lists of 25 words each. The intensity of each word list was digitally adjusted so that the threshold of each list was equal to the midpoint between the mean thresholds of the male and female half-lists. All lists were homogeneous with respect to audibility and psychometric function slope. Digital recordings of the psychometrically equivalent word lists are included on a compact disc.